The Stovebolt Site Forums The Parking Lot Tons 'o Fun 14 bolt axle swap Considerations, Brainstorming, and Solutions

Thanks.

I got the Barnes 4x4 spring perches today. Nice big heavy parts. Gives me a more confident feeling than the trailer ones. What I didn't think about with the trailer ones, until I had them in place under the springs, was that they didn't extend past the u-bolts. Now I know they'll be welded in place, but it just seems like it's a better idea. They will surely support the springs better.

Now I gotta get some tape on them and get to work with the circle template, protractor, or anything else that is round and the right size.

Larry W.

I got the perches marked up after finding a water glass that was a perfect 3-3/8" diameter.

I ended up just tracing the perch out on thick paper with it's existing 2.75" arch in it. Then with some measuring, I got the water glass positioned over the paper in the right spot, maintaining the top of the original arch. Then I traced the new arch into it. Then I cut it out, eliminating the line, to allow for the width of the pen making it bigger when tracing earlier.

I walked it out and checked the fit on the axle tube and it looks good.

Now, knowing that I probably didn't get it perfect, I put a 1 on one side of the paper and a 2 on the other and then I made the same marks on the perches and went ahead and marked them for driver and pass sides too.

Now I marked out the new arch with a silver Sharpie. I used the 1 side of the paper to mark the 1 side of the perch and then I flipped the paper over to the 2 side before marking the 2 side of the perch. This way, if my paper arch was slightly biased to one side or the other, it kept the bias the same on both sides of the perch when I marked them.

Pics:
https://www.dropbox.com/sh/6ojbmgdgwzo6d0d/AACPQg-uE2Bafu2Iw0jYOxvBa?dl=0

Larry W.

Nice, that's about what I was thinking of, a line to trim to with a grinder. Another layout method is to use a compass and scribe the line directly on the part.

Here's yet another way to skin the cat.
PICTURE 1
PICTURE 2

Grigg

Grigg,

If I had the mill, I'd have done the same. I could still just take them up the street and have them done, but probably won't. I'll grind them out. What did you create your drawing on? CAD of some flavor?


I am figuring on pulling the rearend again, and then the hubs again. Level the diff off of the spindles and then grind the perches to fit and also be level to the spindles. There is no real clean spot on the tubes I can see to level from. The real estate is either taken or was ground on to rid it of the OEM perches.

I have new bushings and pins for the springs/shackles that should come today; hopefully the right parts. I need to address the spring slop before welding perches anyway, so rear had to come out regardless. U-bolts won't arrive until next week either.

I bought what I think will be a pretty nice slide hammer kit, but it is still in the box, so we will see. I bet it will be needed for those pins. The cheap HF press should handle the bushings just fine.

Back to brakes.
Ideally I would end up with disc brakes on the front and the rear, with a temporary period of 3-1/2" drum brakes on the rear. But, due to the work and cost of moving the mounts, I am leaning now toward transferring the 2-1/2" brakes from the 3.42 C&C 14 bolt onto this 4.10 housing. This is assuming that they interchange. I have not measured, but assume they will, since as you suggested, the 3.5" backing plates are quite concave, where the 2.5" ones are basically flat. Meaning they used the same flange location but dished the backing plates back an inch to make room for the wider brakes.
https://www.dropbox.com/sh/nv8rla8ibv8ekq0/AAAJjbdPJNGJ9yxqZ_GSlxvCa?dl=0

Yes, the bigger brakes would be nice, but if I can gain an inch on either side, while maintaining at least the same size as the factory ones, that will make me happy for now.

Also, this 4.10 was hoisted into the air by a crane, from one end, when the PO loaded it on my trailer. The brakes at one end are full of oil and will need to be replaced. (No gasket on one axle shaft when I took it apart) I think the 3.42 will have dry brakes and may be OK to re-use. So, quicker, cheaper and OK for the time being.

So there is the plan du-jour. LOL

As always, feel free to influence the plan. Always welcomed.

Larry W.

Not sure what to tell you on the various drum brakes. Not sure They are all interchangeable on a given axle housing because of flange location. Have to measure and see.
I'm sure you can't put dual hubs on a single wheel axle and expect any drum brakes to bolt on.

Do you need 3.42 gears, what will your engine be? I feel that 4.10 is about all a 235 or 228 can pull. 3.73 might be OK with more power, but 3.42 is pretty fast.

You can swap gears in the housings, it's not all that much trouble.
http://www.pirate4x4.com/tech/billavista/PR-ARB/articles/14b_Gear_Setup/

I'd pick which brakes you really want and use them now. I found rebuilding the old drum brakes is expensive.. good shoes are expensive, and drums not cheap either. don't spend time and money on something you don't really want or plan to use.

Grigg

"Not sure what to tell you on the various drum brakes. Not sure They are all interchangeable on a given axle housing because of flange location. Have to measure and see."

I was going to do a quick check tonight. Just measure from the end of the diff housing to the backing plate flanges on each side and each rearend.

"I'm sure you can't put dual hubs on a single wheel axle and expect any drum brakes to bolt on."

Both of these are dual wheel rearends. Pics didn't show that. LOL. Not sure why one would have had 2.5's and the other 3.5's, but I assume they had heavier and lighter duty applications. I have not really verified that they are actually 2.5" as you suggested, but makes sense as they both have dual hubs and different backing plates. Right now it has dual tires at both ends and I can't get to the drums.


"Do you need 3.42 gears, what will your engine be? I feel that 4.10 is about all a 235 or 228 can pull. 3.73 might be OK with more power, but 3.42 is pretty fast."

Nope, sticking with 4.10's. Just wanna swap backing plates and brakes from one dually rear to the other and have a 4.10 rear with 2.5" brakes instead of 3.5" brakes. Rather not disturb the gears, and if this works out, there is no reason to.

"I'd pick which brakes you really want and use them now. I found rebuilding the old drum brakes is expensive.. good shoes are expensive, and drums not cheap either. don't spend time and money on something you don't really want or plan to use."


Might be a few years before I convert the rear to disc, if this 2.5" swap works out. I will assess the brakes on the 3.42 ratio rearend and see what is usable / swappable. That may affect my decision, but my priority would be to get the rear usable and spend the money on the front discs where most of the work is done.

Thanks as always Grigg.

Larry W.

OK, I'm following a little better now.

For determining how and if brakes swap measure and compare the distance from backing plate flange on axle tube to back side of hub where the drum mounts.
For example the 13x3.5" deep drum as on my C&C 14 bolt needs 5-15/16" to fit the whole brake package. Or with shallow drum needs 1-1/4" less.

I'm reasonably certain that only one backing plate (one offset) is available for each shoe width, if this is not so I'd like to learn more about it.

The original 1 ton AD rear brakes are 14" X 2.5".
To use 13" X 2.5" is a step backwards in stopping ability.

I'm looking at brake swaps/upgrades to get more stopping ability to cope with higher speeds and or good sized loads.

Grigg

Ok,

Had to know. Going back out after this.

Brakes look to be 2.5" models on the 3.42 ratio dually. Drums side by side.

https://www.dropbox.com/s/rqlpr65n1zkdwsc/100_4218.JPG?dl=0

Also when I measure the housings they are both 16" and then 11.5" from the back of the 4 bolt flange for the backing plate to the edge of the housing where the axle tube enters it.

As for the brakes, you are correct about the drum diameter. I wouldn't have a clue how to calculate the percent of braking loss there, but since I plan on doing disc on the front...I'll probably give it a shot anyway. I'm sure there are 100 arguments both ways on that one. Newer brake tech, newer tire tech, power brakes down the line.....do those even matter......

Bottom line, I guess I'll do it even if it may not be wise.


Larry W.

That being said...

According to RockAuto; in 1978, the approx year of my 4.10 14 bolt, a C30 truck was available with 13x2.5" drums.

Makes me feel a little better.

Larry W.

If my math is right the percent difference between 13 and 14" brakes is ~7%. Meaning that given same shoe width (and perhaps also assuming same area of friction material) the smaller drum is about 7% less effective. As you pointed out I too expect there is more to consider for a precise difference but still no doubt that larger diameter drum is better.

Again, to compare and figure if the brakes will interchange measure space from the hub where the drum meets it over to the flange on axle, this is a primary dimension as far as how the brakes fit. No other variables or assumptions playing into it.

Ok,

So I went out right after my last post and just coming in from getting the one drum\hub off.

The shoes seemed to be welded to the drum, but in reality, I think they were just stuck a little and the adjuster seemed to be jacked out very tight and wouldn't move. Ended up having to take the pivot bolt loose and put a propane heater under it and that let me get it off finally.

So, from the back of the hub where the drum contacts it, over to the backing plate flange, is 6" on both axles. So, It should be a go. Busy tomorrow, but I will try to mock one up Sunday to see what the gain will look like.

Larry W.

Did some digging around this morning.

It is looking like the 3.42 14 bolt that has the 2.5" brakes I want to transfer may be from a P30 Van. Drum is just shy of 6.5" tall. It has a casting number of 3993578K4 on it, but a Google search turns up nothing. It also has something like F/21 or F721 cast on one of the tabs and then a disconnected 3 nearby.

It would be nice to know what year the parts are.

The shoes look pretty much identical to the 3.5" shoes except for the width.

Pics I took this morning...

https://www.dropbox.com/sh/6g91w373iz6528d/AAB0A5jgKmpmxcq9I9PNbL-Pa?dl=0

This page shows a P30 brake drum, 13x2.5" brakes, that was used for models with 16" wheels. So it's possible that is what mine is. It did have two 16" split rim wheels on it when I got it.

Larry W.

The C&C axle I have came from a P-30 with the 3.5" brakes. I think it would have also had 16" wheels.
Might be just different vehicle weight ratings result in different brakes.

Sounds like mine would certainly have been an auto trans with that ratio. I didn't get a chance last night but I also will verify that the hubs on the two rearends are the same. Everything I have seen says there were only the two I think. SRW & DRW. Both of these are DRW for sure. Studs are the same size and length. Just a little difference in length of the knurled area.

Have not measured them but the one drum I have off looks like it will be ok. Just some surface rust. I'll likely have them touched up and then see. Suprised to see parts are not too bad. Maybe 50 or 60 for all 4 riveted shoes. Complete spring kit for like 5. I'll probably buy delco shoes if possible. Even the drums weren't too bad.

Larry w.

When I bought shoes my guy at NAPA strongly recommended the top of the line shoes. They get complaints of poor stopping distance from the lesser ones, said it is noticeable.

What brand did you end up with Grigg?

Looking at Wagner and Raybestos, both riveted.

BTW,

I think I nailed it down. The 2.5" brake DRUM donor rearend seems to be this application:

https://www.dropbox.com/s/1xuext5xdzpygi4/New%20drum.jpg?dl=0

The brake shoes have a wider application range:

https://www.dropbox.com/s/u3w2no72swhoa9r/New%20Shoes.jpg?dl=0


Larry W.

The shoes I purchased were NAPA "premium" or something like that. Wherever you get them I'd opt for whatever they say is the higher quality option, better friction material.

I already returned all the new drum brake stuff I had purchased after finding the late model disc setup and confirming I can use that.

Yeah,

The two brands I am looking at are the higher prices, no bonded crap. Rockauto breaks stuff up by economy and daily driver and then in the daily driver they usually have a professional item too.

Larry

So, just as a side note.... After reading this post,

http://www.pirate4x4.com/forum/tow-rigs-trailers/619672-14-bolt-disc-swap-cab-chassis-axle.html

I am having serious doubts about ever going to disc on the rear of this C&C 14 bolt while retaining my duals. Which right now, I won't give up.

So unless running 19.5 duals, instead of the 16's referenced, will change a lot of the fitment dynamic; I will likely stay with drums permanently. If the 2.5" drums ever give me trouble or parts are extinct, I will then do any conversion needed to go to the 3.5" SRW drums like you mocked up.

For now, I'll do the 2.5" drums, basically a bolt on, and move on to 250 engine swap, steering, body, etc.

I'm off to measure hubs to make sure they are the same between my two DRW rearends and then work on whatever jumps out at me.

Larry W.

This info/post may remove those doubts you were having about dual wheels and disc brakes.
https://www.stovebolt.com/ubbthread...del_GM_disc_brake_swap_.html#Post1147540

Yes, I'm liking the looks of these late model disc with dual piston calipers and reliable parking brake. They should also be more effective thin the 13x3.5" drums I was considering earlier.

I'll be running single 19.5" wheels, also want a pickup bed.

Yeah, I just got done reading that one before I saw this one.

Sounds really good. As long as I can use that setup on my C&C truck and run my dual 19.5's, I am in. Just not yet. LOL.

I will watch your progress, and at some point I will start hunting up those parts until I have it all ready to go. For now I will go ahead on the 2.5" drums as it is a bolt on, and will get me moving toward engine swap and things that will make it a driver.

Here is a comparison of the fit with the 2.5" drums vs. the 3.5" drums.

3.5"
https://www.dropbox.com/s/1izpzophxaj1qzi/100_4169.JPG?dl=0

2.5"
https://www.dropbox.com/s/9b2beaimn2rtseq/100_4236.JPG?dl=0

Much better. Doesn't look like that much, but I may actually be able to hook up brake lines. LOL

Larry W.

If someone wanted 2.5" drums and even more room they also make a shallower 2.5" drum. I have a single wheel 14 bolt that came with these these drums. Would require spacer or new mounting flange in your case.

Grigg,

"I'll be running single 19.5" wheels, also want a pickup bed."

I assume pickup style, not singled out P30's.

Also, I agree on the parking brakes being a big plus, and I like that you are doing all 3500 style parts.

I am sure that a lot of people will follow this path in the future, and I for one appreciate the effort! You are very detail oriented and it will be nice to go back over the post later to get a parts list and application list.

I might have been interested in the other drums if you had not come up with this disc option. But I'll reserve the fabrication for the discs later.

Larry W.

So, In addition to testing the fit of the 2.5" brakes, I also removed the rear spring on the driver side.

I had no luck with the slide hammer method to remove the pins. It just pulled the bolt out. In the end, I found the secret was to take a brass hammer and drive the pin in flush first. Then I drove them out from the back with a long brass drift. I was liberal with the PB Blaster.

For the spring end of the shackle, I drove it in flush to loosen and then I used my ball joint service kit to push the pin out the other way. I have had this thing for a long time, and use it rarely, but it was great for this and I will use it again when it is u-joint time.

Pics:
https://www.dropbox.com/sh/1oyh29xhiseftyo/AACU8oDhDiwUHUEUA2URB_cIa?dl=0

The worst wear seems to be in the pin that came out of the spring end of the shackle.

All of my spacers seem to be to the outside, so I assume that is the proper position. I hope so, because I won't slide my springs back toward the backing plates. LOL

Not sure I have all the parts needed yet. I have plenty of new pins, but seem to be shy on bushings. All of the ID's appear to be the same, but I have not measured.

Larry W.

Edit:
Later I looked it up on RockAuto and found these, so I think I'll have everything when these arrive. I just didn't go to the right section before.
https://www.dropbox.com/s/rv67wlt57q5j8u6/Bushings.jpg?dl=0

Not sure what you're asking/assuming?
I will run the 14 bolt cab and chassis axle with normal single 19.5" wheels. Because it also measures ~63" WMS same as the original axle single wheel pickup; the pikcup wheels can again be used and will fit in the fenders.

On the 3/4 and 1 ton rear springs, 2" wide, the ~1/2" spacers go on the outside, makes the spring center spacing narrower.
On the larger trucks they use 2.5" wide springs with all the same spring hangers, pins, and shackles.

Grigg

"normal single 19.5" wheels"

That's what I was getting at.

You mentioned using 19.5's before, but you were testing stuff for others, so the P30 duals kept showing up in pictures. When you said you wanted a pickup box, I assumed you meant the pickup style 19.5's, but I never saw them.

For a while there, I thought you might be going for a railroad track look with the P30 duals singled out. LOL.
http://www.bcvi.com/wp-content/them...track-inspector/images/BRE-Hi-Rail-1.jpg

You are going this route then, with a pickup box:
http://s994.photobucket.com/user/Bnabb/media/1950%20Chevy%203600/NewWheelsonBack2.jpg.html

I REALLY like this. May be a project for me in 10 years. LOL
https://s-media-cache-ak0.pinimg.com/736x/f7/d8/4a/f7d84aecc57bc4414d9fbef054429bb1.jpg


Larry W.

Doesn’t seem like it has been 2 years already...
I’ve started again on this 14 bolt axle project. If time allows the meat of this thread could turn into a nice tech tip.

Making progress on that, read here https://www.stovebolt.com/ubbthread.../14-bolt-axle-swap-info.html#Post1249600

Thanks,
Grigg

Thank you guys for all of this information.
After I get the 41 on the road, I want to go with DRW. The 41 3/4 ton already has a H052 SRW in it. I've already put 19.5 wheels on it. I have an 8' bed for it and plan to extend the rear fenders, as shown in Larry's last pic above.
Thanks again!