Preamble: This is now an old thread... it has some good ideas and some that didn't measure out to be useful. Please accept my apology for not following through with a tech tip and clear concise step by instructions with pictures, part numbers and such. I haven't had time and probably won't. If you're willing to read through it you can figure out how to adapt P-30 brakes to an old big bolt. Several folks have followed through and it works nicely. It didn't really work for the 3/4 and 1 ton.. kind of but makes for a wide axle, or requires narrowing an axle beam. Not really a success
EDIT: picture links don't work Webshots died then Picasa did too...
This thread is kind of a continuation of this earlier one but different enough to start a new thread in an attempt to not be to confused by the last. Also check out this tech tip my first method for making a big truck disc brake front axle was to narrow and weld a P-30 or 3500HD axle, this is not simple or quick. The following method I think will be better than the cutting and welding method.
It is my intent to come up with a method of installing disc brakes on AD big trucks 1 ton through 2 ton. Much if not all of this should also apply to 3/4 tons. Also consider these methods for 41-46 trucks, possibly even with the original heavy duty 2 ton axle, or an AD (48-54) truck front axle is supposed to be a bolt in swap. AD axles have 26-13/16" spring center bolt to center bolt hole measurement.
**** If you're willing to research axles and widths this same method could work for Chevy and GMC trucks from (best I can tell) 1941-1978 Because for all those years an axle was offered with a 1.109" kingpin, and if your truck already has one of those axles the spindle swap described here should work. Or if your truck doesn't have an axle with 1.109" kingpins you can very likely bolt one in from a larger truck of the same body style. again, do your own research and these examples and measurements should be a great start. ****
In short the idea is to use an original axle, likely from a 2 ton, and adapt later model spindles and caliper brackets to it. For a single wheel truck it will also involve adapting single wheel hub/rotors to the new spindles.
First let's get everyone up to speed on what we're talking about: WMS --- Stands for Wheel Mounting Surface, this is the flat surface on the hub that the wheel bolts against. Likewise a measurement described as WMS to WMS is the width across the axle between those surfaces. P30 --- Is a model of GM chassis commonly used in the 70's, 80's and 90's (and?) as step vans, bread trucks, and RV's. Many but not all of these have I-beam front axles with either 8 lug or 5/10 lug hubs and disc brakes. 3500HD --- Chevy truck (with pickup style cab)in the 90's that also had a I-beam front axle and shares some but not all of the same parts with the P-30 I-beam axles. Dual wheel --- Deep offset type wheel, and even when used as a single on the front axle we'll call this style a "dual wheel" Single wheel --- Wheel with a more or less centered mounting surface.
A few WMS to WMS measurements just for reference on the axles I have here. AD 1 ton single wheel front axle is 58.25" (If you're curious the rear axle measures 62.625") AD 1 ton dual wheel front axle 66.25" AD 2 ton front axle is 69-15/16" AD 2 ton NAPCO front axle is approximately 72.5" (courtesy of Napco Man) AD COE 2 ton front axle Approximately 71.25" (can anyone confirm?) GMC 400 series 3 ton with Clark F466 front axle, about 72.75" P-30 8 lug front (dual wheel) is 81.625" P-30 5/10 lug front (dual wheel) is 82.062" 3500HD 5/10 lug front axle (dual wheel) is around 79.5" (still need to get an exact measurement)
How wide are the I-beam axles themselves? It's hard to measure, so a pretty simple and accurate method of at least comparing them is to measure from the centers of the kingpin lock pin holes, I like to insert a 1/2" bar in each and hook the tape measure on one and measure to the inside of the other. The following are my width measurements from center to center of kingpin lock bolt holes: 48-53 2 ton 52.625" 47-54 AD COE 2 ton 54-54.5" (courtesy of vwlfan) 41-46 2 ton 53.75" with heavy axle (courtesy of Billy Marlow) GMC 400 series 3 ton with Clark F466 front axle, about 54.75" P-30 8 lug 61.75" P-30 5/10 lug about 62" (might turn out to be same as the 8 lug axle) GM P3500 HD(baby school bus) with 5/10 lugs 62.0625" 3500HD 5/10 lug __.__"? AD 1 ton single wheel front axle ~49.75" AD 1 ton dual wheel front axle ~49.75" (my own previously narrowed 3500HD axle ~49")
How wide is an AD 3/4 ton up to 2 ton front axle from spring center to spring center? Understand that the springs are closer together at the front than the back, they're not parallel as many later axles are. Center to center of spring center pin holes in the axle is 26-13/16 inches.
Some questions you might have: Q)Why not use a 1 or a 1.5 ton axle beam? A)They are the same (as each other) and appear substantially lighter weight than the 2 ton. They use a 0.921" kingpin that is also much shorter and the thickness of the end of the axle beam is around an inch less, so not a good match for the newer spindles. Q)What are these axles rated for? A)A P-30 axle is rated about 5,000 lb, and the 2 ton is rated 4,500-5,000 lb, nice that they are so similar! Q)What's the difference between a P-30 5/10 lug axle and a 3500HD axle? A)The main one we'd be concerned with is the steering linkage. The P-30 is setup like our old trucks are with tie rod behind axle under springs, the 3500HD has tie rod on front and above springs, and drag link is there too. Q)Did they ever make a single wheel P-30 disc brake axle? A)No, if it has disc brakes it will be a dual wheel type axle
If these disc brake swaps revolve around swapping newer P-30 spindles onto old AD axles there needs to be some similarities, here they are: The thickness of the I-beam axle end where it fits into the spindle is the same for both P-30 and 2 ton AD axles, About 3.050". The angle that the kingpin leans in, known as kingpin inclination angle, best I can measure is the same for both axles. Kingpin length is essentially the same, and the lock pin groove is in the same place.
Now it would be to easy if everything was the same... here is the major difference: The kingpin diameter on the 2 ton axles is 1.109", and on the P-30 it is 1.179".
Two methods of adapting the P-30 spindles to the old axle: Use thicker walled bushings, but I've been unable to find any ready made ones. You can order oversize bronze ones and turn and bore them to suit, probably have to mill the grease groves too. Or you can make thin sleeves to press in the kingpin bores in the spindles to adapt them to the original size smaller OD bushings. So far I like this idea best. I'd use green loctite sleeve retaining compound so they stay put, and in the future new kingpins and bushings are an off the shelf item.
The 1.109" kingpin kit you would use is NAPA # 262-1016. There are other similar kits but this is the best choice from what I can see because it comes with gaskets for the caps on the P-30 spindles, not steel plugs like the old 2 ton had, it has bronze bushings not plastic, and has a ball thrust bearing not a thrust washer. It's also cheaper and easier to get than the other possibly suitable kits.
Simply put if you swap a 2 ton axle I-beam only to an 8 lug P-30 axle and the result is 9.125" narrower, so WMS to WMS would be 72.5" for a dual wheel 8 lug disc brake front axle. Is this suitable for a 1 ton AD truck? ...No, the original WMS is 66.25" so it'd still be 6.25" extra wide or tires would be about 3-1/8" further out each side, not fully under the fenders. Is it suitable for a newer than AD truck? Might be depending on width and adapting the springs to the axle.
How wide would a 5/10 lug P-30 or a 3500HD axle (same spindles and hubs)with an AD 2 ton axle beam end up? WMS to WMS should be 72.8125 within 1/8" or so. That's 2.875" wider than an original AD 2 ton front axle, or only 1-7/16" wider per side, I can't see any problems with that. Or better yet look at it another way, it's only about 1/2" wider than an optional NAPCO front axle!
For the single wheel trucks not only would you need to adapt the spindles and caliper brackets from an 8 lug P-30 to the 2 ton axle, but you also need to find a single wheel hub and rotor to fit the spindle and caliper/bracket.
I've searched and searched and the best possible rotor/hub that I can find is a NAPA part number 4885580. It's a GM combined hub and rotor that has the same 12.5"x1.5" rotor that the dual wheel version that comes on the P-30 axle has. Here are the critical dimensions, look at this sketch for clarity. https://picasaweb.google.com/lh/photo/WPE6TH44cNiB2d-tiFQ0ptMTjNZETYmyPJy0liipFm0?feat=directlink Measurements in inches are from rear surface of rotor, from WMS, and from outside faces of installed inner and outer bearing cones
As you can see the rotor position in relation to the inner bearing is essentially the same, so the rotor sits where it's supposed to and fits in the caliper. Also note that the dimension "C" distance between bearings is the same. The big and expected difference is position of the wheel mounting surface, and in this case it is 3.45" per side, or 6.9" narrower for the whole axle.
Now, don't get to excited because this single wheel hub and rotor won't fit... It uses a different smaller inner bearing, NAPA LM501349 and won't slide on the spindle. But luckily enough the outer bearings, NAPA 15103-S are the same!
The P-30 spindle uses a (inner or large) bearing with a 1.688" ID. The new single wheel hub uses a bearing with a 1.625" ID. A 0.063" difference.
The way to make this fit a good way is to turn that 0.063" off the inner bearing journal on the spindle. Then off the shelf bearings and hubs work in the future. More/better/different bearing option of a larger bearing and thin adapter sleeve, keep reading or click to skip right to it. https://www.stovebolt.com/ubbthreads/ubbthreads.php?ubb=showflat&Number=778876#Post778876
An alternative method might be to adapt the hub to fit the larger P-30 bearing cup, this is a 0.109" difference, and I'm not sure about the depth, or if there is enough material in the hub. Not a good plan because you have to modify parts to replace rotor/hub.
The grease seal intended for the new hub fits the P-30 spindle perfectly. It's very common and 1/3 to 1/4 the cost of the P-30 seal, so that's a good thing. NAPA seal # 21771
Now the big question, is this whole thing narrow enough to fit in an AD truck? Starting from an 8 lug P-30 axle WMS to WMS of 81.625: the new WMS width could be 9.125" narrower with an AD 2 ton axle beam swap, and 6.9" due to the hubs, for a total of 65.6" That's 7.35" wider than an original AD 1 ton, and that's disappointing
To start with the original axle could be wider and the tires could still fit, but not that much wider... The limiting factor seems to be the 68" width measured inside the front fender lip at bottom of opening, same both front and back edges. Some different wheels with a little more inset might work? I'm still going to see what this all looks like, but not sure how it'll turn out.
One thought is to narrow a 2 ton axle I-beam 5.25" because then half he U-bolt holes could be reused, and a plate made like this to land the springs on and the other two U-bolt holes. That would leave the resulting axle about 2" wider WMS to WMS than original, which would be fine, 1" per side might not be noticeable to the untrained eye. Admittedly not a simple or fun solution, but could be a workable one.
Another thought is narrow a P-30 axle beam a lot and still use spring mounting adapter plates like above. Narrowing it 16" results in original single wheel WMS to WMS, but several inches narrower at the kingpins, so less steering angle, and not much (enough?) room for the P-30 steering arm to not hit the springs. Narrowing it about 14" might improve the situation, but then the 2 ton axle narrowed (as above) looks easier/better for same final width.
Looks like a lot of research here. I discovered that the front axel on my 41 1ton had the same parts as the 46 1/2 ton. Both with 6 lug. I compared them all in the master parts list
While it,the 1/2 ton kit, was not listed as fitting a 41 1 ton I took the gamble and it all fitted and worked perfectly.
In 1946 they changed the 1 ton axel so it will not work on that year.
I was sure my 1 ton would never be used to capacity and any disc brake system is better than the old drum system.
Here's the condensed info for a 1.5 ton heavy and 2 ton disc brake upgrade. No need to even remove the axle beam from the truck!
If you have a 1.5 ton with the light axle (thread or press in grease caps) or a 41-46 1.5 or 2 ton also with the light axle then first swapping to an AD 2 ton axle beam would be necessary. (Or consider a 41-46 heavy 2 ton axle and double check all the critical measurements.)
In addition to the info below you'd also need to narrow a tierod, this can be done by using the one that comes with the P-30 axle and cutting it approximately 9-1/8" shorter on one end and rethreading it to fit the tierod end again. Consider choosing the right hand threaded end, taps are more common than left hand taps, but left hand taps are available if need be.
The draglink will also need a solution and it should be reasonably simple to assemble from off the shelf ends (different lengths, threads, and tapered ends are available) and a sleeve to connect them, just as the P-30 used. If you have a ball stud type end on the pitman arm you can remove it and have it reamed for a modern draglink end, or can swap pitman arms for one from a newer truck with the tapered hole already. Like this one from a 52 Chevy 1 ton.
Note that if you want to use the original steering box you want a P-30 axle as the donor, not a 3500HD axle with the different steering setup.
Originally Posted by Grigg
...method of adapting the P-30 spindles to the old axle: ...make thin sleeves to press in the kingpin bores in the spindles to adapt them to the original size smaller OD bushings. I'd use green loctite sleeve retaining compound so they stay put, and in the future new kingpins and bushings are an off the shelf item. A real simple way of making those sleeves is to ream the worn P-30 king pin bushings to proper size to accept the 2 ton bushing, I've done this already and it works very nicely.
The 1.109" kingpin kit you would use is NAPA # 262-1016.
Originally Posted by Grigg
...How wide would a 5/10 lug P-30 or a 3500HD axle (same spindles and hubs)with an AD 2 ton axle beam end up? WMS to WMS should be 72.8125 within 1/8" or so. That's 2.875" wider than an original AD 2 ton front axle, or only 1-7/16" wider per side, I can't see any problems with that. Or better yet look at it another way, it's only about 1/2" wider than an optional NAPCO front axle!
Just for info, I measured 1.5 or 2 ton AD front fenders (on the truck) to be 72" wide inside to inside of the lip at the bottom edge both front and rear of the wheel opening.
Request for careful measurements If you have one of these trucks and can add to the info please do.
A WMS to WMS measurement for an AD 1 ton dual wheel truck front axle.
For an AD COE in addition to a WMS to WMS measurement also need an accurate width of the axle beam from center of one kingpin lock bolt hole to the other?
Any other trucks/axles you have that might fit into these plans and we don't already have info on?
Grigg, If I get some time this next week I will measure the WMS of my '49 3800 DRW. Loving what I am seeing. Fingers crossed that this would become a workable option.
Of course, by swapping out the spindles and hubs, etc., makes using the P-30 a very simple option. Disc brakes, radial tires, man now all I need is A/C and power steering...
Grigg, For the record I just wanted to take a second to say thanks to you and the rest of the "grandmasters" for posting this kind of info. I am sure I am only one of a ton of people eagerly awaiting for you and them to solve this puzzle so we can all go forward and benefit from your solution. Thanks!
Grigg, If I get some time this next week I will measure the WMS of my '49 3800 DRW. Loving what I am seeing. Fingers crossed that this would become a workable option.
Jon, if you've had a chance to measure please do let us know what you found, and I'll see if we can answer the question about how well this works for AD dual wheel 1 tons.
Been a long time since I've posted here. But I am still interested in these big bolts and this is the brake/spindle swap I have been thinking about for the last 6 months. I have a question though, who is the actual front axle manufacturer and what is the model for the 5/10 lug P30 front axle? Spicer? Dana? Eaton? I am trying to source the assemblies from a large truck wrecker and he wants to know the manufacturer and model of the axle, I can't seem to get him to look it up by truck application.
Rockwell.... but I've never seen it listed or referred to by that, I've only noticed the Rockwell logo on some of the parts. I suspect it is better known as a GM axle which makes a lot of sense because I've never ever seen one under anything else (from the factory).
If you can't get a wrecking yard to find something by application you need to find a real wrecking yard...
Here's more info on the single wheel hub and fitting them on P-30 spindles, the inner bearing is the problem.
Here's what I found about bearings.... Already knew outers are the same NAPA 15103-S so we'll just be talking about the inner wheel bearing, the big one.
The single wheel hub to use is NAPA part number 4885580. It uses inner bearing "Chicago Rawhide BR35" same as "Timken SET45" same as "Timken numbers LM501349 cone and LM501310 cup" The ID is 1.625" and OD is 2.891"
The stock P30 hub/spindle takes inner bearing "Timken numbers 26884 cone and 26823 cup" ID is 1.688" and OD is 3.000"
Ideally there would be a bearing cup with the small 2.891" OD that fits the single wheel hub and a compatible cone with the large ID of 1.688"
It has been suggested that the following bearing may be a partial solution. "Chicago Rawhide BR50" same as "Timken SET47" same as "Timken numbers LM102949 cone and LM102910 cup" Has the correct OD of 2.891" and the ID is a larger than needed at 1.781"
So two or four options, 1: The spindle can be turned 0.063" so the stock single wheel inner bearing SET45 fits. If a large radius is kept in the corner strength shouldn't be an issue after removing only 1/32" per side. 2: The bearing SET47 could be used. It has the same 0.770" assembled width as SET45. To fit on the spindle a thin wall bushing would need to be made with 1.688" ID and 1.781" OD... That's only 0.093" difference so 0.0465" wall thickness. One option if just making the sleeve the right size to start with doesn't work is to shrink it on the spindle and then turn/grind the OD to final dimension. 3: find a suitable conversion bearing with 2.891" OD and 1.688" ID (No luck so far) 4: Have that bearing made; which apparently is possible but at what quantity and price?
More on option #2! Parker shaft wear sleeve number WS1976 with ID of 1.687", OD of 1.813", and 0.625" wide could be a great starting point, still needs to be ground or turned down about 1/32" after installation. (could not find yet a another different bearing that would work without turning the sleeve)
Hey guys, I'm the proud new owner of a '54 3800 and am looking to tackle the disc brake conversion problem as well. I've been looking online and over in the 67-72chevytrucks.com forum and found a guy who converted to disc on his 1951 3800 in basically a bolt on fashion. He descibes his final approach at post #22. I'm trying to figure out his front bracket right now and see if I can get one made as a one piece steel water jetted instead of welding two plates together. Below is the link to the post.
And for pictures: He gave me the link, and just got his permission to share. I'm not sure what bearing he used, but I am assuming that they are ball bearings.
Just a thought couldn't maybe a 4X4 front hub assy with disk brakes be grafted onto the Big Bolt front axel.The older ones have sort of link pin type set up so without an axel shaft in the way you could run a the pin all the way through.You would then only have to run a bolt through the center of the hub with a Washer or metal disk and gasket to seal it up. There are some tall and not so wide 16 inch tires. These ars close to looking like a 7.50- 20 tire .So they would not change the apperance to much Or if you know a good welder you could make a nice tube axel also useing pieces of the 4X4 front axel & hub this would be very east to do. The recivers for the front hubs are pressed into the axel tubes and welded so cut them off chuck them up in a lathe turn off the tube and weld .For a jig you would have already figured how long the tube has to be ,so you would bolt your spring pirches to the springs lay your tube accross center it and only tack the perches on.Then level the truck up side to side .Next you would have to a bar turned so it would fit down through the top and bottom pin holes on the hub reciver with enough extra so you could place that magnetic thing that you can check for angle (sorry forgot the word)next you would need your tires on the rims so you can set the height of the truck .Now you can tap the hub recivers into the tubes ,you would have turned them in the lathe so that they are snugg but if you heat them a little to turn them to set the caster once the caster is set tack them good .Now unbolt it from the truck put on a welders table clamp it down good tack a few baces on so it has no chance to move and weld that sucker up .Now you have disk brakes just an idea
Last edited by PAUL NOLZ; 12/22/201111:29 PM.
1948 Chevy 2 ton flatbed ex fire truck , and various motorcycles .
Hey All!, After reading about axles, wheels, and tires until my eyes fell out and to be honest I became a bit discouraged I came across an idea that I wanted to bounce off the forum. It may be borderline heresy to say in a place like this but I will brace myself and apologize ahead of time. Keep in mind that my truck means the world to me and is one of my last real connections to my grandfather. However, other than the cab (the exterior), the Cresci dump, and the front axle (which has to go), there is absolutely nothing stock or original about it. My grandfather was all about modifying it to suit his needs and or what he had available at the time. Its a 1954 6100, and it is my understanding that the front axle is just a small hair under 70" wide. So has anyone given any real thought about swapping in a pair of 2.5 ton rockwells with the hubs "flipped"? The width is 69.25 inches with them flipped. The truck would be much more valuable and useful to me as a 4 wheel drive and thus I would have a bit more justification to invest my time and money into it. If 69.25 inches is too narrow I don't think it should be too bad $ to get one side custom shortened and then just cut the tube on that size to the size I need. It looks like I might have a line on some reasonable rockwells, and wheels and parts should be a whole lot easier to come across. My grandfather always wanted a NAPCO truck so this is kind of interesting way of getting my truck close. Thanks.
Rockewlls would make for a very tall truck and just as low gears although I think aftermarket faster gears are now available. Still leaves you figuring out brakes? Mounting the front axle to the springs might be difficult and taller springs are probably required.
Certainly you should look into it, but in my opinion I bet you find it's not a great idea.
Grigg I'm looking to put some front and rear discs on my '54 1-1/2 ton truck. What is a good formula on determining the right diameter and thickness of the rotors for safety reasons? I will be using the stock 2 speed rear end and will keep the 235 with the sm-420 4-speed.
There are photos on this build link that show the caliper mounts I made and the set up front and rear. Uses F550 calipers. The rotors are from a company that sells disc brake conversions for the 2 1/2 ton Rockweel axles for mud trucks. http://rides.webshots.com/album/550039908qGswfS
Thanks, There are countless ways of doing a disc brake conversion.
My intent is to use easy to get parts new and or used and keep the machine work to the bare minimum. So far with the P30 parts that comes down to just a couple bushings.
hi im new here i have a 1947 3/4 ton with the 8 lug bolt pattern i have looked for a disc brake setup for a few years i finally found someone to build a kit for me it was a little bit more than a kit for the 1/2 ton pickups i was the first one to get the kit built the company is called RPM Eng the owner is ron his phone 3 is 760-329-1886 give him a call he should be able to help with a disc brake conversion if you have any ? you can contact me at [email protected] for more info
Any measurement on wms-wms for 1 ton drw front axle?
No, not yet, do you have one you can measure?
I don't care to speculate what it might be... to be good info to work from we need the real thing to actually lay a pair of straight edges and a tape measure on to accurately measure.
I have one but it will probably be a bit before i can pull the wheels. I agree a direct measurement will be best.
they way i did the calculation was to use the measurements rom the manual. If you take the difference between the center of the outer tires in the back and the mean of both tires int eh back- that should be the offset of a dually wheel. take that and add it to the center of the front tires and thats how much longer they make the axle so the same dual wheel will fit. that came to 66" I'm pretty confident it is correct because I found a measurement by soemone with a 1.5 ton and it was within 1/4" I think all that is different between the trucks front axle is something in the hub accounting for the small difference...
Hopefully I can take a true measurement in the next month or two. This really sucks not having the truck at my place where I can work on it even in any 15 or 30 min stretch I'm "free"
Hi all! I am new to the forum, and just purchased a 1938 1-1/2 ton stake truck. My very 1st thought was,"how will I get disc brakes to fit this"? Having read this post, I am wondering, why not find a rotor setup that fits the stock spindles? This may be a silly question, or something I have missed. Just wondering?
I've tried/considered other ways myself, the P30 parts option is the one I like most at this time. With more or less work most of your options will work in the end. The brake capacity, reliability of the system, and availability of parts are all worth considering.
My goal in finding a suitable solution for the mainly AD trucks (but most any year with 1.109" kingpin) is something that is factory for another vehicle (for reliability) and takes very little fabrication or machine work, ideally none. What I've come up with for the dual wheel trucks requires a spare later model (P30)axle for parts and you need to ream or bore the existing P30 bushings out to then press the original size bushings inside them (or turn adapter bushings). The rest is just swapping parts, no disc adapters or caliper brackets to fab.
Les, (Roadmarks,) from Raleigh NC, here. I was just rereading your fine article on disc brakes for 3/4T and larger trucks, and now find that the pictures are no longer available. The new service, "SMILE," requires a membership. If there is anything you can do to make the photos publicly available again, it would be greatly appreciated!
Would it be easier to bore the axle out and use the 1.179 kingpin? You'd have to handle a big heavy piece but you wouldn't have to mess with keeping a .035" wall bushing concentric. Just wondering if any one has actually run the bushing setup yet and whether they cut them themselves or farmed it out?
Edit: Now that I've looked at your wonderful photo collection, Grigg, I see that you likely meant the p30 kingpin is 1.375ish diameter. Now it all makes sense. Looks like something I could whip up at work. How much clearance did you allow from the adapter bushing diameter to the stock bushing?
Sorry, Webshots has gone belly up as far as I'm concerned, it's agrivating... I have switched over to Picasa but don't have all of my same pictures up there yet, I do have them though somewhere or another. Don't know when I'll ever have time to repair all these dead links.
Would it be easier to bore the axle out and use the 1.179 kingpin? You'd have to handle a big heavy piece but you wouldn't have to mess with keeping a .035" wall bushing concentric. Just wondering if any one has actually run the bushing setup yet and whether they cut them themselves or farmed it out?
Edit: Now that I've looked at your wonderful photo collection, Grigg, I see that you likely meant the p30 kingpin is 1.375ish diameter. Now it all makes sense. Looks like something I could whip up at work. How much clearance did you allow from the adapter bushing diameter to the stock bushing?
Boring the old axle will change the fit of the kingpin lock bolt/pin and require even more modification. Boring the axle also removes metal from around the kingpin where it's pretty important. Making the bushings fit the spindle and using original 1.109 size kingpins is the safer and I think simpler option.
The bushings aren't all that difficult, it can be as simple as not removing the P-30 bushings and just ream them out to fit the new bushings in.
From my notes, (confirm dimension and fit with your own measuring tools to fit your exact parts) A P-30 bushing, NAPA part number 262-8273 fits in a about a 1.299" - 1.300" bore. An old GM 2 ton bushing NAPA part number 262-8081 fits in a 1.229" - 1.230" bore. So I'd ream the P-30 bushings out to very nearly 1.229" whatever it takes for a proper press fit of the new bushings in. Then ream the new bushings inline to fit the 1.109" kingpin.
Again, I use kingpin kit NAPA 262-1016, it has metal bushings, thrust ball bearings, and is cheaper than other NAPA kits that would also work.
The pins look to be more than .070" difference in diameter, according to your pic, and the other pic showing the big bushing the small bushing, and the sleeve you turned shows that too. I get what you're saying about the axle and why that wouldn't be ideal, but the bushing numbers don't jive. Unless I'm lookin at the wrong pics, seems the p30 bushing is already bigger than the od of the smaller one. Whatever, it looks like a very viable solution.
Not sure what pictures youre looking at, I have also adapted some big Spicer axles, that might be what you're seeing.
The P30 spindles to 2 ton axle works as I describe, have a set of nested stock P30 and 2 ton bushings here on the bench in P30 spindles. Kingpin is 6.344" long for both 2 ton and P-30.
Sorry the picture links have died, they are all in a new album listed in the very first post of this thread.
No, nothing more condensed than this thread. It works well for the 1.5 and 2 ton trucks with 5/10 lug wheels. Doesn't so easily work for the single wheel trucks, and don't have dimensions on an 8 lug dual wheel truck to know how well that works out.
What is the WMS to WMS measurement, and year truck? To get an accurate measurement I remove the wheels, set the steering wheel to straight ahead, put a straight edge on both hubs so they're as close to center up and down as you can and level to the ground. Then measure the width between them both forward of and behind the axle, then take the average.
Just a thought ,it wouldn't be that hard to make a pair of hubs and bolt a pair of smaller calipers one top and bottom .The only small problem would be bleeding the bottom one .You would have to take it off to bleed so the bleeer is pointing up with something between the brake pads.This would be a cheaper way to to go if have a lathe and your a good fabricator Just a thought Paul
1948 Chevy 2 ton flatbed ex fire truck , and various motorcycles .
I don't have part numbers for the spindles, rotors I've had no trouble looking up at NAPA.
Paul, I have several lathes and am probably a decent fabricator... I'm absolutely sure the above method of swapping existing P30 parts is by far cheaper, faster, and less trouble than machining brand new hubs from scratch as well as designing and fabricating caliper brackets.
The beauty of the P-30 spindle swap for the 1.5 or 2 ton AD trucks is the only machine work necessary is boring and reaming some bushings.
HELP... I've got a '00 chevy HD3500 solid axle with discs and trying to swap sides to get the center-link behind the axle to go into my '64. It's got 4, 1 1/8 bolts that hold the hub to the king pin but trying to pull the calipers off. EVERYTHING came to a screeching halt!!
It's NOT like the regular sliding caliper, it's got a tapered hex/allen screw holding what looks like the slider.. The caliper looks like its' cast INTO the hub...???? I've 'googled' and all I see is the 8-lug regular style caliper. not what I'VE got..
SO, I'm thinking IN THEORY that It'll work swapping the sides to use the stock steering box, but the 'bus' one is SURE BEEFY! Man that thing is big. Does anyone know if swapping messes up my angles and any 'ackerman' effect of the geometry??
I may have to make an adapter or look for another power box.
OK, gone through the whole thread and it's mostly condensed to spindles, king pins, yadda yadda. Now are all you guys that are doing/done this swap STILL using the Hydro-VAC and different prop valves or something else?
I'm going with a Hydro-BOOST set-up and would love to see some diagrams/exploded views of how to hook the lines up.. Someone forgot to mark them when they took them off for ME...
OK, gone through the whole thread and it's mostly condensed to spindles, king pins, yadda yadda. Now are all you guys that are doing/done this swap STILL using the Hydro-VAC and different prop valves or something else?
I'm going with a Hydro-BOOST set-up...
This thread is for and about swapping the spindles, king pins, rotors and so on. It does not cover the master cylinder and booster aspects of the swap, did not set out to and don't want to in this thread. That said, hydroboost is what I have used and it works very well.
I am having a super hard time finding a P30 axle for my conversion. The car-parts.com site does not have a listing for P30's so it's really had to locate one. Most of the yards in my area (Tampa FL) have scrapped them. If anyone has a link to some I am getting desperate. I just really need the spindles hubs and steering arm. Thanks Dave
Look on craiglsist for an older nearly dead RV. I would expect Florida to have plenty of RV's sitting around. You may find one at a good enough price to pull the axle(s), scrap the rest, and make your money back. Many RV's have low miles also.
Most all of the Chevy/GMC RV's I find are A arm style. Still looking but starting to look out of state (desperate). I found a Kodiak axle and was wondering if I could cut off the end of that axle and weld it on to mine. Can that be done safely?
I know at one point in this conversation you guys were talking about bearings. I found this on another site:
"I finally found some for the 3/4 ton and 1 ton trucks. On Chevofthe40s.com Part #909025R(outer) #909026R(Inner) I contacted customer service and they assured me that these were taper roller bearing replacements for the 3/4 ton and 1 ton trucks.
Take it for what its worth...Let me know if anyone has tried these bearings. Nate __________________
OK, well maybe I should have checked the site before I posted. It's not there any longer but maybe someone could cross reference the part numbers??? Nate
I installed the tapered bearings when I did the disc brake upgrade on my 1 Ton. I can't compare any difference since I never drove my truck prior.
Wayne 1938 1-Ton Farm Truck Stovebolt Gallery Forums 1989 Silverado 1996 Mustang GT convertible When I die, I hope she doesn't sell everything for what I told her I paid for it!
I bought mine from them for my 1951 GMC 1 ton and they appear to be good quality bearings, I am probably going to instal them this winter. P/N are 909026R and 909025R.
Dave
1966 Chevrolet Caprice 2 Door Hardtop (396 Big Block) 1951 GMC 9434 5 Window (waiting on a 292 transplant)
Dave, Thanks for the info. Wow, I did not realize how much those bearings are! Glad to know that they are available because that has been a huge portion of the discussion for switching to disc front brakes. Nate
You guys are incredible!Ive got an old 65 c60 truck Ive been wanting to do a disc brake swap on and thought I was limited to using parts off of a newer c60-70 truck,This gives me more options.
Grigg, I have a 3500HD complete front axle I was going to narrow and swap into my 50 model 6400. But after reading through this thread Id like to try and swap just the disc brake setup off the HD front axle onto my truck. I know you used the P30 setup, but do you have any info, instructions, or parts list for doing the same with my 3500HD parts??
You can do the exact same spindle and brake swap with the 3500HD front axle as you could with the P30, those parts are the very same.
The difference is the steering linkage and the arms or bell cranks bolted to the spindles. The P30 tie rod and drag link are in the same places as they are on your old 2 ton, this makes for very little adapting (can usually use original tie rod, reaming arms to fit if necessary). Also makes steering and drag link simple to adapt to the original box. The 3500HD has all the steering linkage in front of the axle, a "Y" type it might be called where the drag link is anchored to the tie rod. This setup may or may not easily fit above springs and under oil pan. The major problem is you'd need a different steering box to make it work. I have used this setup on my truck but at the time I had no idea the P30 version even existed, that is what I should have used.
<<<The 3500HD has all the steering linkage in front of the axle>>>
What do you think about switching sides so that steering linkage is behind axle? Calipers would be on front side but that wouldn't matter. Im pretty sure the caster is built into the axle so it shouldn't affect alignment??
It would mess up the steering geometry, the Ackerman angle. Ideally when looking down on the truck if you draw a line from each kingpin back to the center of the rear axle then also on those lines are the centers of your tierod ends. If steering arms are forward of the kingpin the tie rod ends ought to be wider than the king pins. If you flip it around they would still be wider but now well outside this line from kingpin to center of rear axle.
Even if it worked out you need a different steering box..
Just use the P30 steering arms and save yourself a lot of trouble.
They come on a complete P-30 I-beam front axle. Even if you found the part numbers and tried to order them from GM I suspect it'll be easier and cheaper to get a whole used axle.
ok new to the big bolt world here and I'm wanting to do the conversion for my 49 chevy 4400 1.5 ton. disk brakes are going to be a must for me as i am going to use it as a tow rig and want to be able to stop my load. i have been over this entire board and many others and no one answers the questions below clearly. i see that it is possible to do a disc conversion but i can't find info as to how to really start the process.
any and all info will be greatly appreciated my number is 2517098264 if you would rather call and walk me through something other than typing it. or if you are close to mobile alabama id love to see what you have done.
Q1. is their a bolt on kit? Q2. is a axle swap for possible 4x4 an option that may be easier? Q3. Where can i purchase the kit if it is available or are their part numbers that will make it easy to pice together a kit? Q4. would the current drums on the truck be sufficient with just a hydro boost system replacing the stock master cylinder.
Axle swaps are always possible. My '48 has an '80 Firebird disk brake rear (3.73 limited slip), so I have four wheel disk brakes. I used a conversion kit for the front.
I would not use drum brakes on your truck, especially not the Huck brakes that it came with stock. I would recommend four wheel disk brakes for your application.
Finding axles is a matter of measuring. to make sure it will fit your truck. There may be someone on the board who's already done the swap for a similar truck, so keep asking questions.
Paul's post above seems to be pointed toward the small trucks.
I will answer to the larger trucks.
Originally Posted by cleiser25
ok new to the big bolt world here and I'm wanting to do the conversion for my 49 chevy 4400 1.5 ton. ...i have been over this entire board and many others and no one answers the questions below clearly. Q1. is their a bolt on kit? Q2. is a axle swap for possible 4x4 an option that may be easier? Q3. Where can i purchase the kit if it is available or are their part numbers that will make it easy to pice together a kit? Q4. would the current drums on the truck be sufficient with just a hydro boost system replacing the stock master cylinder.
Your questions are not new, and have been answered, see if these help.
Q2. No, because of the quite narrow track width on these old trucks most any 4x4 front axle you find from a later vehicle is much too wide; or if narrow enough is from a very small vehicle and therefore not strong enough. Add to that the task of fitting a transfer case, driveline, and shifters; not a simple job all total.
Q3. answered with Q1.
Q4. Likely. Hydroboost would give you an easier pedal but you still have the same braking area and fade considerations of the old brakes, you still have the old brakes. -Most folks doing a conversion and improvements to the brakes also have future parts availability in mind. One attraction to disc brakes is not having to find or have rebuilt the old brake parts that are slowly becoming more and more obsolete, for example the drums are not available new. I think in most cases people putting disc brakes on plan to use the truck frequently, so ease and cost of rebuilding/replacing the brakes later is an important consideration.
Sorry for the confusion. If I had more time I'd love to continue to research this and complete the work I've already started for my own trucks.
As to scrapping the axle or not? Can't say without knowing what you're trying to do with it. In general though, no, don't scrap it; the 3500HD axle has a lot of good parts.
The downside to the 3500HD axle in regards to our old chevy trucks is the very different steering linkage/design. I think in most cases, and for sure if using the original steering box, you'll want the two bell cranks/steering arms off of a P30 axle, not what comes on the 3500HD axle.
Here's the condensed info for a 1.5 ton heavy and 2 ton disc brake upgrade. No need to even remove the axle beam from the truck!
If you have a 1.5 ton with the light axle (thread or press in grease caps) or a 41-46 1.5 or 2 ton also with the light axle then first swapping to an AD 2 ton axle beam would be necessary. (Or consider a 41-46 heavy 2 ton axle and double check all the critical measurements.)
In addition to the info below you'd also need to narrow a tierod, this can be done by using the one that comes with the P-30 axle and cutting it approximately 9-1/8" shorter on one end and rethreading it to fit the tierod end again. Consider choosing the right hand threaded end, taps are more common than left hand taps, but left hand taps are available if need be.
The draglink will also need a solution and it should be reasonably simple to assemble from off the shelf ends (different lengths, threads, and tapered ends are available) and a sleeve to connect them, just as the P-30 used. If you have a ball stud type end on the pitman arm you can remove it and have it reamed for a modern draglink end, or can swap pitman arms for one from a newer truck with the tapered hole already.
Note that if you want to use the original steering box you want a P-30 axle as the donor, not a 3500HD axle with the different steering setup.
I have a 59 gmc 350 2 ton truck with I believe to be a f045 front axle. Does post #725572 from page one apply to my vehicle? Thanks
Ok. I think im following this now. Yes my kingpins are 1.109. I haevnt mearsured them yet but according to a data sheet that I found they are 1.109. I will measure before any work is done. So id like to summarize this and let me know if im correct or if I missed anything.
I'm starting with a 2 ton 59 gmc.
What I need to do: Source p30 spindles, caliper and brackets, hubs/rotors and tie rod. Ream the p30 kingpin busings to fit the OD of the 2 ton kingpin busings. Aprox..070. Press the p30 busings into the p30 spindle. Press the 2 ton bushing into the reamed p30 bushing. Narrow the p30 tiesrod. Assemble and enjoy.
That's pretty much it, here with a few minor details added and changed and some pictures.
1-Source 5/10 lug P30 (I-beam axle) spindles, calipers and brackets, hubs, rotors and tie rod. PICTURE 2-Purchase new Kingpin kit NAPA 262-1016 or equivalent. PICTURE 3-Rough machine/bore the old used steel/bronze P30 kingpin bushings close to 1.22" ID PICTURE 4-Press these used now bored P30 bushings into the P30 spindle, green loctite is a good idea. 5-Finish ream the old P-30 bushings to fit the OD of the new 2 ton kingpin bushings. 1.2300" ID 6-Press the new 2 ton bushing into the reamed p30 bushing in the spindles. 7-Ream bushings in line with each other and to fit new nominally 1.109" kingpins. PICTURE#1PICTURE #2 8-Narrow the P30 tierod. 9-Reuse an old one or assemble drag link from new parts (I have not done this part yet to know all the details/options/part numbers) PICTURE 10-Assemble and enjoy. PICTURE
Grigg I'm alittle confused about step 7. I understand the reasoning for line reaming the bushings but the bushings in step 7 already have an ID bore of 1.109. Which is the size of the king pins. If we line ream the bushings in step 7 wouldnt that then make them out of tolerence for the kingpin fitment?
Ok. That makes sense. Do you have any ideas on where to start looking for these salvage parts? Maybe a salvage yard that deals in p30 step vans that does shipping.
I suspect your best bet is to visit a few yards planning to buy a complete front axle, probably cheaper than having them disassemble one and you get everything you could need.
Also check craigslist, these axles were under motor homes and they can sometimes be had real cheap complete if the RV part is trash.
OK I found a place that carries new and used parts locally. Here is there website for anyone looking for parts www.workhorsesupply.com
Grigg after speaking to the guys at workhorse I've got a new question. They have told me that the p30 step van had two version. One with 16" wheels and one setup with 19.5" wheels. The differences are the tie rod is different between the two and the 16"uses a one piece rotor and hub where the 1.5 uses a separate rotor
Do you have any input on this. I'd like to do this swap with the 19.5 setup. Will it all still work and do you know which tie rod you used.
Last edited by Grigg; 11/19/20155:17 PM. Reason: add info from duplicate post
You want 5 lug front (fits 10 lug wheels). The most obvious difference in the two versions as they describe is the smaller one is 8 lug. The other is 5/10 the lug which only came with 19.5 wheels.
I would use complete everything from a 5/10 lug I-beam axle as mentioned previously.
Look at this PICTURE It shows both the 5/10 lug and the 8 lug axle.
The P30 with the 5 lug front axle has a 10 lug rear axle, very same way many of these old GM truck do. So the wheels have 10 lug holes and fit front or rear, just the front hubs have only 5 studs.
I would not pick an axle based solely on the wheel size fit to it. They also made 8 lug 19.5 wheels.
I think if you have a 59 GMC 2 ton then you have 6 lug Budd wheels. The bolt pattern you get with this swap is 10 lug on 7.25" bolt circle with 5.25" center hole, hub piloted. Most common wheel by far is a 19.5". Some 22.5" wheels exist from the later 50's and only used on some Chevy 1.5 tons.
Last edited by Grigg; 11/19/20155:29 PM. Reason: more info
Grigg thank you for clearing that up. Makes sense now. You have got to be the quickest responder I have ever encountered on any forum. Thank you for your help and all the homework you have done on this swap. Once I get my parts I will take some pics of my swap progress. I'm sure I will have more questions once I start tearing down. Thanks
Grigg! Thank you so much for sharing your work here on the Stovebolt. I wan't to upgrade from drums to disc for my project as well.
I'm reading, and reading, and reading, and finding myself amazed at the amount of information that's in the place. I'm feeling a lot more optimistic that I can bring this project of mine to life.
-David
1953 2-Ton GMC
I'm a machinist... because engineers need heroes too.
Having invested several days digging through piles of truck tires and rims at the salvage yards looking for 20 inch 8 bolt stud piloted Budd wheels for my '56 C6500 I can tell you that the 5/10 bolt 19.5 rims are still available. dan
Yep...lots of 19.5 rims out there. Mine are from a 1998 Chevy 3500 4x2 Dana 80 HD Duallie w/wide track. But they also came on some '94 to '02 Dodge 3/4 & one-ton trucks as well as '88 and later Ford F-350 & 450 Super Duty rigs.
While I much prefer the look and height of the original 20" wheels, I needed the gearing of a newer axle plus tubeless tires so I went with the Dana rear axle. It has a lug pattern that matches the original ('46 1.5 ton in my case). I did have to make 1/4" spacers for the fronts since the center pilot hole on the newer rims are that much larger but it was no big deal.
I'm hoping to do something about the brakes on my '52 GMC 9700 (Canadian built 3 ton) I see the GMC 400 series 3 ton with Clark F466 front axle was mentioned for width at the front of the topic, but didn't see much about it after (also not sure if this would be the same axle as mine or if the Canadian trucks ran something different) Are there big differences from the 2 ton to 3 ton axles?
The springs are mounted parallel on a 400 series GMC and they taper in narrower on the 2 ton and smaller AD trucks. To know if this spindle swap might work on your axle find or measure kingpin diameter and thickness of axle end where the kingpin passes through.
Okay... but if its the rear hold down springs that need to be replaced... Napa... OReileys... no one carries nor can they get them... how do i get the springs then??
I've been reading this post over and over. I think I get it for the most part, though it probably would be easier with picture links that worked (Grigg - I did find the ones in your signature, All pictures / Disk brake upgrade...) This would all be likely easier if I could find one of these golden P-30 axles to at least see, I finally saw what a 3500HD front axle looks like on a '94 today (Not so many of those here either). Still no luck with acquiring either, but I imagine in time I will find one.
Things I'm not quite sure of (More for Grigg, as most of the questions are on pics from his album): I see the (I'm assuming) 2 X P-30 axles, but both with different DRW style rotor / hubs, but by the end of the album it looks like you've gone with an SRW style rotor? Also, it looks like 8 on 6.5 pattern? I see mentioned earlier there is lots of talk of the 5 /10 bolt pattern used. Are the P-30 spindles different between the 8 on 6.5" and the 5 /10 bolt patterns, or once you find an 8 on 6.5", you're committed to that pattern due to caliper mount? (rotors are different od?) If yes to using the SRW rotor, are you using a DRW rim on it?
I did confirm both my kingpin size, and the axle thickness are the same (Ie P-30 is possible fit) on my Canadian 3 ton (but I still don't really know what my axle is), and yes, the springs are parallel on mine. Nobody remembers changing anything axle wise (front or rear) on my truck, and that's going back to the early 70's. (It has an odd bolt pattern, not the usual pattern other Canadian 9700 3 tons have, Mine is 5 lug on 8", with a 6" hub bore, 20" rims both front and rear axles) Long story short, it would be nice to see what the stock 2 ton drag link / tie rod setup is, to confirm if mine is the same, different or more importantly whether or not it could work. My steering arm appears to thread into the spindle and is held on by jam nut below the axle. It goes aft and connects to the tie rod (behind the axle), and comes up above the axle, link connects to it, parallels the leaf springs and heads aft to the steering box...
Thanks,
Matt
Last edited by 40_chevy; 02/03/20186:29 PM. Reason: correction, had a brainfart
The 8 lug and the 5/10 lug axles are essentially same except for rotors/hub (diameter) and matching caliper bracket.
Your unusual hub centered wheels are “Motor Wheels” Not that uncommon on a GMC like yours, and some other makes of trucks too.
You say parallel front springs, which makes your truck about like an American GMC 400 series, even bigger than the 1-1/2 and 2 ton fenders right? The steering arm attachment you describe sounds like what Spicer does, perhaps a Spicer axle/ though it doesn’t really matter who made it, it is what you have. If your axle has same thickness at the end where the kingpin fits very likely you can swap these spindles with appropriate bushings. However... a 3 ton truck might be a little big for P-30 front axle components, weight wise. Also, the 5/10 lug pattern on 7.25 wheel options are 19.5” (look real small) 20” (tube type) or 22.5” (hard to find, and only 38” with 9R22.5).
Check your kingpin diameter, it may be larger and allow larger spindle swap, bigger than P-30 and different better bolt pattern choices. Look in my photo album for 53 GMC which gets larger Spicer spindles and brakes with 6 lug Budd wheels.
My pictures do show 8 lug and 5/10 lug and single and dual wheels. Different stuff going on, the 8 lug and single wheel (with smaller diameter rotor) is for 3/4 and 1 ton, except troubles with overall axle width. The 5/10 lug is best for 1.5 and 2 ton.
Sounds right from from I've seen, Re the 400 series. Attached a few photos of what my fenders, and linkage looks like. (probably much better than my description) There is a small portion of the kingpin sticking out the top of my spindle, It measures 1.105" so a little bit smaller but I suspect it's the same 1.109" kingpin. For size ref in the pics those front tires are 7.50/20 (and not that it matters but my rears are 8.25/20) I edited the last post, had a brain fart when I noted the bolt pattern, so I gave you the wrong info there. Should have read (large pattern) 5 lug.
Matt
Last edited by 40_chevy; 02/03/20186:37 PM. Reason: additional info
Hi. I have started a restoration project on a 1950 Chevy 2 ton truck. I have a P30 van to swap the rear axle over and hopefully swap on the front spindles as per this thread. I was just wondering if anyone has finished doing the swap and how it drove after, caster alignment ect with the p30 spindles. Thanks.
Grigg, I had a question about best ways to go as I was reading your tech tip on the 4BT swap where your cut 10” out of a P30 to use it on that build. Would that be a reasonable way to go since I want to convert my 1.5 ton 4400 to disc brakes. I don’t have a 2 ton axle, so I was just thinking of finding a 5/10 front and rear combo and do the cut down and weld. Otherwise if I use the methods you described earlier in this thread I would have to source a 2 ton axle as well as the 5/10 P30 axle correct?
The cutting and welding on the P-30 axle is a lot of work and some risk, not something I recommend anymore. It solved my problem at the time, before I learned of the spindle swap.
The 2 ton I-beam with the P-30 spindles and brakes is a very easy job, low risk. Take the time to find a 2 ton front axle beam, they're usually about free for the taking and some labor to extract it.
Grigg, I have a 3800 DRW and I have an 88 8 lug 19.5" stepvan. My plan was the front axle shortening approach and now my beacon of knowledge is no longer recommending this course. Is the spindle swap applicable to the 3800? Would the axle need to be replaced with 2ton or will the 1 ton work? What risk have you identified with the axle shortening (assuming the axle gets welded in proper alignment, which is where the work comes in)? Thanks for any info you can provide Chuck
I don't have enough measurements yet to know if the P-30 spindle swap (8 lug) is useful for the 1 ton DRW trucks. You can measure your original axle width and compare with measurements given earlier for what a 2 ton axle with 8 lug P-30 spindles on it would measure.
(I'm sure it does not work with single wheel 8 lug stuff on P-30 spindles on 2 ton I-beam, it's still overly wide...) With luck your measurements will workout on the DRW version, I have not ventured down that path to know.
These P-30 spindles do not fit on a 3/4 or 1 ton axle, but the 2 ton axle beam (48-54) does bolt under the same model 1 ton trucks.
The risk is not having the axle welded properly, that's up to you. It's not terribly difficult for a competent welder and with some careful alignment of the pieces before welding. Altogether though it's a lot of work and time to cut, prep, weld, and pretty up a welded axle beam. The P-30 spindle swap on a 2 ton axle beam can be done in an afternoon once you have the parts and pieces at hand and clean, reaming some bushings is not tricky or difficult, low risk.
I’ll be honest, I didn’t read through all the posts yet, but figured I’d ask first, then read. Lol. So, I have a 55, 2nd series 6500 2 ton truck that I want to convert to 4 wheel disc brakes. Are there any kits that are basically a bolt on? This thing is a beast. Came stock with a 265 V8 and has a regular bed with widened fenders, not a stake bed.
So, I just found this awesome website!!!! 12 long phenominalpages on the front axle issue that I have been pondering for my 54 ford code C 500. Probably my biggest concern as I plan to use it to tow my racing trailer distances of up to 5 to 600 miles from my home in Orlando. At first I didn’t realize I was on a Chevy website. I see there is much crossover on this issue between different cab over engine trucks in the solid in front axle. Your moderator GRIGG is a phenomenal moderator as he has lasted on this one thread since at least 2012 or 2011. When I finally got in and saw there was more than one page I about fell out of my chair when I saw there were 12 very long pages on this topic and others too. It makes everything make so many other automotive websites Pale in comparison. This goes for the any of the Ford websites as well as there’s little to any help or information regarding cool old trucks like ours. I haven’t read the full 12 pages yet as I just discovered this yesterday. But I do look forward to gleaning much information not just about the front axles the brakes but, about other things related to cool vintage trucks whether they be Chevy Ford Dodge international whatever. Thank you guys so much for making this happen it’s gonna be very helpful and fun.
Martin '62 Chevy C-10 Stepside Shortbed (Restomod in progress) '47 Chevy 3100 5 Window (long term project) ‘65 Chevy Biscayne (Emily) ‘39 Dodge Business Coupe (Clarence) “I fought the law and the law won" now I are a retired one! Support those brave men/women who stand the "Thin Blue Line"! Hug a cop! USAF 1965-1969 Weather Observation Tech (I got paid to look at the clouds)
After reading this & other disc brake conversions my brain hurts & am now more confused then ever how to do a front axle 1 ton conversion for a 1 ton panel. Unless someone has a condensed version of how to do it??? Or is there a way to change it over to a 6 bolt disc brake set up??? Mean while I figured I'd google it & see what popped up. Anybody heard of these folks or have used their kits???? https://www.tsmmfg.net/chevy-gmc-8-lug-truck-complete-front-disc-brake-kit-1847.html Thanks......joe
Last edited by TooMany2count; 02/04/20195:53 PM. Reason: added a question
~ Joe Donate Blood, Plasma, Platelets and Sign Your DONORS CARD. The Life You SAVE Might Be Someone You Know and LOVE. Two possibilities exist: Either we are alone in the Universe or we are not. Both are equally terrifying. ~ Arthur C. Clarke
I mainly found this information as it pertains to my 1968 C50 but it may be usefully for our other fellow members. This information came from user rkn463 over at the chevy 67-72 forum. http://67-72chevytrucks.com/vboard/showthread.php?t=704713
It seems that he discovered that the disc brake spindles from an 1989 C60 box truck could be adapted to the 67-72 medium duty F050 5000lbs front axle. rkn463's plan was to transfer 1968 truck body onto the 1989 chassis. To have the wheels still tucked under the fender, he chose to adapt the new spindles to the older, narrower axle. See below for more details.
"A few months back my attention came back around to the truck. As much as I like the 327 in the 68 this will be a working truck and the 366 from the 89 is a better option. Plus it already has all of the accessories like power steering/hydroboost pump ans A/C compressor already mounted. Further measuring looks like the hydroboost will bolt up to the 68. That front axle thing is killing me so I get to looking at the SPIDs on both trucks, they both have an F050 (5000lb) front axle, it is just that the 89 is 6 inches too wide. More measuring and it looks like the 89 spindles might fit the 68 axle. I researched on the internet and found this:
I found that the bore in the older axle needed to be enlarged by .0070 and I could put the 89 spindles on the 68 axle. That was the deciding factor, I'd just go ahead and use the entire 89 frame and drivetrain in the 68 but with a narrower axle.
Rather than pull apart the 68, I pulled the front axle from the 70 GMC frame that I had acquired and took it to a local machine shop to have it bored out. I also ordered a set of kingpins online. This was December 2015. After a few weeks of waiting to get that axle back I pulled the 89 in the shop and removed the brakes, spindles and axle. Things got held up at the machine shop and I finally got the 70 front axle back in early March 2016. I cleaned it up, repainted it and reinstalled the 70 axle in the 89 truck with the 89 spindles. It went smooth except that the stops on the steering linkage did not line up with the stops on the axle so I had to drill and tap a new hole."
I'm not sure if this helps those with older models but I hope this helps someone.
The source is NAPA, that's their part number. I just called and ordered a kit myself, 70 some dollars and no shipping if willing to wait a few weeks for the normal NAPA trucks to bring it. As of today, 6-25-19 They have one in Atlanta, Memphis, Oklahoma, LA, and Utah among other places I assume, and 5 kits at the manufacturer's distribution warehouse. It is still a good part number and when those are gone more will be available. My parts guy at NAPA recalled that part number was (in past years) a very common kit, even before looking it up in the computer.
I'm green when it comes to big bolt trucks and am looking to put disc brakes on my 1930 1 1/2 ton. Am I correct in my initial reading that this thread covers later models? If so, can anyone point me in the right direction? Thanks.
After reading this & other disc brake conversions my brain hurts & am now more confused then ever how to do a front axle 1 ton conversion for a 1 ton panel. Unless someone has a condensed version of how to do it??? Or is there a way to change it over to a 6 bolt disc brake set up??? Mean while I figured I'd google it & see what popped up. Anybody heard of these folks or have used their kits???? https://www.tsmmfg.net/chevy-gmc-8-lug-truck-complete-front-disc-brake-kit-1847.html Thanks......joe
I also am interested to know if anyone has any experience with the website Joe refers to. I looked at the website and it appears that they are using 78-85 Monte Carlo calipers rather than pickup calipers. I wonder it those could handle the heat dissapation required of a bigger vehicle like my nearly always loaded 8800lb 1-ton,
1951 3800 1-ton "Earning its keep from the get-go" In the DITY Gallery 1962 261 (w/cam, Fenton headers, 2 carbs, MSD ign.), SM420 & Brown-Lipe 6231A 3spd aux. trans, stock axles & brakes. Owned since 1971.
[quote] I looked at the website and it appears that they are using 78-85 Monte Carlo calipers rather than pickup calipers. I wonder it those could handle the heat dissapation required of a bigger vehicle like my nearly always loaded 8800lb 1-ton,
It probably has to do with size. I used C1500 calipers and had to do some grinding to make 16 inch wheels fit.
Wayne 1938 1-Ton Farm Truck Stovebolt Gallery Forums 1989 Silverado 1996 Mustang GT convertible When I die, I hope she doesn't sell everything for what I told her I paid for it!
Most of the heat capacity is in the rotor/drum. The lining is a relatively good insulator compared to the iron of the rotor, even semi and full metallic linings. The swept area of the rotor, that area the width of the pad x the circumference of the rotor, is one of the main determining factors in brake rating. The size of the caliper determines the clamping force and thus the deceleration rate that can be applied to a given gross weight. If you can clamp tighter, you can stop faster. If you have big rotors, you have more time available before overheating and you have more leverage against the turning wheel.
Mac :{)
1962 K10 short step side, much modified for rally 1969 T50 fire truck, almost nos, needs a few things
Sweepleader, I have no doubt that what you say is correct; It's just that I have brake heating problems on the front as it is and boiling brake fluid makes the brakes really erratic. Think of repeated stops from 60 mph for the lights on Bangerter Hiway in Salt Lake City. I need to do something soon as the drums are pretty thin. Rears are OK.
1951 3800 1-ton "Earning its keep from the get-go" In the DITY Gallery 1962 261 (w/cam, Fenton headers, 2 carbs, MSD ign.), SM420 & Brown-Lipe 6231A 3spd aux. trans, stock axles & brakes. Owned since 1971.
I did not mean that you should not use discs, only that the caliper does not determine the heat capacity of the brake, the rotor does for the most part. If the drums are not doing it for you, for sure, switch to discs. I put discs on my '62 K10 and they are great. I was able to swap from a '72 K10, they are easily 3x the brakes as far as heat goes. When a disc heats up it expands toward the caliper, not away from the shoes as a drum does.
Mac :{)
1962 K10 short step side, much modified for rally 1969 T50 fire truck, almost nos, needs a few things
I also am interested to know if anyone has any experience with the website Joe refers to. I looked at the website and it appears that they are using 78-85 Monte Carlo calipers rather than pickup calipers. I wonder it those could handle the heat dissapation required of a bigger vehicle like my nearly always loaded 8800lb 1-ton,[/quote]
Good afternoon,
The calipers we use for this kit, are actually from a K20.
This thread is about using P-30 parts to adapt disc brakes.
It is not a catch all thread for any sort of disc brake conversion. If it were it'd be less helpful and very hard to search and make sense of. (not that it's easy keeping you head wrapped around just the P-30 details and possibilities)
Please start a new thread or find an existing thread to discuss various other disc brake kits or conversions.
