The Stovebolt Site Forums The Parking Lot Big Bolts Disc brakes for 1.5, and 2 ton trucks

I have the same questions. I'm interested in making this save so other uprade kits are welcome.

Yes, there are kits available.
1947-1955 Chevy/GMC Truck Power-Disc 6-Lug Brake Kit, but you need to talk to the vendor to make sure they'll fit your truck.

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.


Your questions are not new, and have been answered, see if these help.

Q1. Yes
Discussion on the kit as one is installed
https://www.stovebolt.com/ubbthread...isk_brake_kit_for_2_ton.html#Post1085686
Long thread about developing and offering the kit for sale, it is a sticky thread in the parts for sale section
https://www.stovebolt.com/ubbthread...rake_conversion_on_a_46_.html#Post708681

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.

If you would like to do the P30 brake swap as discussed earlier in this thread this post will get you started.
https://www.stovebolt.com/ubbthreads/ubbthreads.php/topics/725572/Grigg.html#Post725572

after reading all this..... i'm dumber than I started. so. do I scrap the 3500 h.d. axle or not?

55 ist. series 1 1/2 ton c.o.e.

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.

Is that any help?

sorta. thanks. good job by the way.

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

Does it have 1.109" kingpins? If so then yes.

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#1 PICTURE #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?

The new bushings come undersize so they can be reamed to fit, this is standard practice for kingpins/bushings.

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.

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.

Realized I double posted. What do you mean 5/10? Are the 19.5 step van hubs 10 lug or 5? Why would I want the 5 lug front

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.

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.

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

Dan,

What did the 8 stud Budd 20's originally come on?

Mike B

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

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

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.

Thanks for the extra commentary Grigg, I appreciate all of the research you have put into this area of our trucks.
Chuck

First time poster here.....

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.

No kits for the big trucks that I know of.

Griggs, is that for the front or rear? Or both?

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.

Hello there, would you please share the name of the website? Thank you.