Bolt pattern change advice 6 to 5

[greg_h]

For the back story, my dad bought a 54 Chevrolet 3100 back in the mid 60s. I have owned it since the late 70s. I finally got to the point in life that I tore it down for some major refurbishment. He also at that time put a set of vintage E-T torquethrust wheels on it using 6 bolt to 5 bolt adapter plates. I know they are not correct to the truck but they are all I have ever known it to have so they are correct to me.

I always hated the adapter plates. They resulted in bad suspension geometry and I always thought they were unsafe as they had screw in studs that tended to work their way out over time.

Part of the upgrade was to do 5 bolt "the right way". The fronts were easy. Car front drums from the same year. The rears not as easy. Moser Engineering said they could weld and re-drill the flanges for the new bolt pattern. That is until I sent the axles to them. As it turns out, time is no friend as when they weld up the flanges, they are too hard to re-drill. They cannot make new axles as the bearing surface is too large for their equipment. They say someone with an end mill may be able to do it. I am no machinist so I don't fully understand the obstacles.

What their suggestion is is to cut the rear end housing ends off and weld on later ends to get a different size bearing and the bolt in style axles vs. the C clip retained design. At that point, they could make me a set of axles to fit. Essentially, the $90 drill job just turned into a $700+ ordeal. I foresee problems with backing plates, brake design change, e-brake cable issues, and more,

Has anyone gone through this or have advice/suggestions? I want to retain the torque tube design as it is a hydra-matic truck so a later rear end as a whole is out of the question I think. Is there a set of axles that would be the correct length and spline to work with the old rear end components with the new axle ends and the 5 bolt wheel pattern? That could save the custom axle part of the project. Looking for advice or past experience.

Thanks,
G.H.

[dwcsr]

try http://www.strangeengineering.net/ or https://www.markwilliams.com/
I think they are sending you the long way round to fix the issue. Its easier for them but not for you

[mr48chev]

I'd think that possible the problem isn't their equipment's capacity but what available axle blanks They have.

Another one to try might be Dutchmans motor sports. http://www.dutchmanaxles.com/c-clip-axle-pair.html

On the other hand a 54 Chevrolet Car takes the same rear wheel bearing as a 54 Chevrolet 3100 truck. I don't know if the axle shafts are close to the same but it is worth checking out. I did some research and the differential carrier gaskets are different so swapping the axle housings won't work.

[Dan in Pasadena]

Why not swap out rearends? Am I missing something?

[mr48chev]

I'd have to believe that he wants to keep the closed driveshaft and matching trans.

It would be a lot simpler to go to a 5 on 4-3/4 open drive rear axle and transmission of choice. That is a reasonably easy one day swap. At least it was when I was 27 in 1973. Now that I am 69 it would take a lot longer.

I think that the problem with having custom axles made is that most of them are set up for CNC operation and the blanks come in certain set

[dwcsr]

Originally Posted by Dan in Pasadena

Why not swap out rearends? Am I missing something?

He has an original hydramatic that uses a torque-tube and he want to keep it that way

[greg_h]

Originally Posted by dwcsr

He has an original hydramatic that uses a torque-tube and he want to keep it that way

yep...found a machinist willing to tackle the project that says "no problem". Keeping the link posted earlier just in case. Thanks!

[mr48chev]

Cool beans, let us know how it comes out and what was done to get it changed over.