Need help on reriveting a ring on a 3.4 rear

Cross posting from Pre-War. I have a 1940 56S but got a 3.4 pumpkin (from a 54 Century I think) to replace the current 4.44 rear. The replacement 3.4 rear has loose rivets holding the ring gear. The mechanic who is working on it got 5/16 bolts to replace those but today he finally got out one of the old rivets and he measured at 11/32. So the replacement bolt would be too loose. No 11/32 bolts at Fastenal. He is stuck - any ideas out there?

Cheers, Dave

Have your mechanic use rivets again.

Correct size are available.

Using bolts which have larger heads than rivets can sometimes not clear your housing and as your rivets were loose the holes are going to be out of round to some degree. Rivets will expand to ensure a tight fit again.

Sigh. May have to, I guess, I will talk to him abt it tmw.

Cheers, Dave

This thread may help

http://forums.aaca.org/f165/1936-buick-special-ring-gear-rivets-306661.html

Stuart, yeah, I did see that and when he said he got 5/16 bolts I figured we were good to go since they are apparently good for a 36. I guess I am surprised that they apparently went to a larger size in the interim.

Cheers, Dave

This was my solution to the problem for my '38-40. I want to put the 3.9 gears in it. Made this modification, but I havnt put the gears in the car yet..

The sleeves are a press fit on the bolts and in both the gear and carrier. The bolts are grade 8.

It should be OK, but the jury is still out. The bolts and steel sleeves are plenty strong enough in shear since the rivets would be dead soft anyway.

Cool! Where did you get the sleeves or did you machine them yourself?

Cheers, Dave

If you go with nuts and bolts, use the appropriate bolts with castle nuts and safety wire. There are a dozen places for things to go wrong. One loose nut between the gear will lock the rear up. Great fun spinning around twice at 60 mph...not so great fun flipping thrice after that. Late 55 used a bolted ring gear with bolts threading into the gear. I don't know if tapping threads into your ring gear is feasible or not. I have a (free) carrier that had the ring gear bolted to it (ring and pinion went to Australia...if that would help.

Yeah I understand. I spoke with my guy this morning and he is looking at leaving the rivets in place and welding it to the carrier. Yes I know that is a one way option but it's not like these rears are unobtanium. Another option is having a machine shop drill out the holes for a close fit with 3/8 bolts.

Cheers, Dave

I machined the sleeves myself. To keep the nuts from coming off, I cut the bolts close to the nut and then peined the end of the bolt over (kind if riveting). Drilling all those bolts for safety wire would have been a lot of work - and I'm lazy.

Any time you weld something that has been hardened you are looking for trouble!!

Don - since welding is way outside my wheelhouse - are you talking distorting the gear or weakening or even cracking it? Or something else?

Cheers, Dave

I was assuming you meant welding the gear to the carrier.

The gear is at least case hardened and any heat high enough to melt and fuse the metal of the two (welding) is going to severely, adversely affect the metallurgy of both the gear and the carrier.

That being the case, there may be a chance of cracks occuring.

I wouldn't chance it.

Just my opinion

Yes I know that is a one way option but it's not like these rears are unobtanium.

Might be easier, cheaper and safer to just get another that does not have these issues. Even with an endless supply of free ones, the redoing is a pain if it does not work.

Don - OK, understand. And my guy has also nixed this option as well. Looks like he will take it to the machine shop. Sigh - most expensive rear end rebuild ever!

Old-tank - Agree, but this one is a bit rarer - a 3.4. If we run into any more trouble I may have to fall back to the old 4.44. Actually I thought I was getting a good used rear that I could at least get by with for a few years, maybe leave the rebuild for the next owner. But the carrier and pinion bearings were shot so it went from there. I suppose we could just leave it as is but my mech said that the loose rivets were causing 4 to 5 thousandths of slop making proper adjustment very difficult, probably leading to more problems sooner rather than later.

Hey, it's only money, right?

Cheers, Dave

With that much slop in the rivets, total shear failure is just a matter of time.