Replacing a yoke on rear axle


#1

I have a 1980 Chevy G30 1 ton van with a corporate 14 bolt rear axle. The yoke on the axle is bad, and I have another one to replace it with. I read the manual to see if there was anything special I needed to do, and it sounds like theres a special way to tighten it, but the manual isnt very clear. From what I can read, it sounds like I need to mark the nut, washer, yoke, and axle, count the number of threads exposed, and tighten the nut back to where it had the same number of threads showing and all the marks are lined up. Is this the right way?


#2

Yes…But is more theory than science. They assume the replacement yoke is EXACTLY the same dimension (length) as the one you are replacing. When it was assembled at the factory, there was a “crush sleeve” between the two bearings you are squeezing together when you torque down the nut. You can’t crush the sleeve again, so your manual is trying to obtain the same torque value as was on the nut originally, which is impossible…

I would follow the directions as carefully as possible, but in any case leave no play or slop in the pinion shaft (that’s what the yoke mounts on). As you are approching the correct spot, keep trying to wiggle the shaft back and forth against its seal. At first, it will move a little. Tighten it down until ALL SIDE TO SIDE PLAY is gone, then just a LITTLE bit more. That’s about all you can do in the field. I would lock-tite that nut so it can’t come loose.

The CORRECT way is to remove the yoke, the seal, the front bearing, and TRY to fish out the old, crushed sleeve. Then slide in a NEW sleeve (if you can find one) and put it back together and torque down the nut to factory spec crushing the sleeve in the process…


#3

Aside from an emergency field repair, I didn’t think the “crush sleeve” was reusable. Does anyone have experience reusing one and leaving it in there for a long time?


#4

Yes, I have done that. You can’t believe the torque required to start the sleeve crushing. It requires powerful pneumatic tools IMO. I did one the “correct” way. The next one I just reused the crush sleeve and did exactly what Caddyman describes. Ran fine for years and never had any trouble.


#5

To properly set up the rear end you should replace the crush sleeve, but this requires removing the carrier because you need to set the pinion bearing preload w/o the carrier in place.

I have replaced yokes and pinion seals w/o replacing the crush sleeve by using the ?scribing? method you mention, but you have to very careful. The scribing method attempts to get the pinion preload back to the previous state by turning the nut back to the same location. This is crude at best. If it?s too loose you will have end-play in the pinion after the diff has a few miles on it, or if it?s too tight you risk applying too much preload to the bearings which can result in over heating.

I never use impact wrenches or air tools when I tighten and set pinion bearing preload. It can take over 400-lb-ft of torque to begin to crush a new sleeve, but I always use a cheater pipe or breaker bar to insure I don?t over tighten. Once the sleeve begins to crush and remove all end play from the pinion the bearing preload will increase VERY quickly and air tools are a sure way to go too far. If you got too far you have to disassemble, install a new crush sleeve and start over. As you add preload you have to keep checking bearing preload with an in-lb torque wrench and compare it too the specs. Different specs for used or new bearings.


#6

Of course you are right about the correct way to do this work and I don’t think anyone can disagree with that. However, most DIYers aren’t going to pull the diff apart to do this and will attempt the easier method if it yields acceptable results. I have done this in my driveway and even with a large truck, there isn’t much room to hold the assembly while trying to rotate a 3’ cheater bar, especially with those initial torque requirements. That’s why I mentioned using a pneumatic gun to get it started. Much like your caution about being careful in the scribing method, you have to use your head with the pneumatic tools too. I had no problem setting the torque limit on the tool and starting the sleeve crushing without going too far. Although, your caution is well taken and should be noted for anyone doing the work this way. I don’t think anyone would suggest continuing to set the preload using an air tool, it’s just a means to get it started in a confined space.

Anyway, my point in responding was to address the scribe method versus the difficulty in using a new sleeve for the DIYer. I think it works well enough to get acceptable results, especially on a nearly 30 year old rear end. YMMV.