Pinion pre-load...

PeteVS

PeteVS

Well-known member
Last year, I started to assemble a banjo rear (first time for me) with a new 3.25 ring and pinion. I got the rear all disassembled and cleaned up. Then, I loosely assembled the bearings and race onto the pinion, heated up the casting and got the pinion assembly into it. So far, so good. Then, I started to set the bearing pre-load. I supported the banjo assembly by the pinion shaft in an old 6 x 6 coupling in a pipe vise. I started tightening the main pinion nut. Turn the nut and "goink!" The bearing wasn't sliding smoothly- it would jump with each twist on the nut. Tighten again, "goink!" Too loose. Tighten again, "goink!" Still too loose. Tighten again, "goink!" Feels good, but maybe just a little more. This time, no "goink." "I think I'll stop here," I think. So, I slip on the washer, then the lock nut and then go to bend over the tabs with a hammer and drift. "GOINK!!" Oh no! Now it feels too tight! I agonized over this for a few months.
Pinionloosensm.jpg

Today, I set up a little pusher (You can do ANYTHING with a couple of threaded rods!) and "goink," now it's loosened up. I now have it set so it feels right. (Bruce is missing a part for his K R Wilson pinion preload torque meter.) Should I have put some NEVER SIEZE on the pinion shaft before I started? Also, should I leave it a little on the loose side while I set pinion back lash and then disassemble and reset the pre-load? Thanks for any experienced advice here!!
 
This time stop when it feels good :D but you feel some drag.
And don't leave it loose; Set it where its going to be for the back lash. If I skipped any more easy ones just ask.........
 
Pete, here are the numbers I have stacked up:
Pinion bearing torque: A-B type, 35—47 inch pounds, Model 18 1932-4 20-25 inch pounds, 12-16 later rear 1935-48

KRW tool has no spring, but what I did last time was to simply find some big regular socket that was able to crudely snag the splines plus several adaptors to hook the big socket to a tiny inch-pound torque wrench.
 
maybe you need a pair of these ford script wrenches for that job,

the last `32 rear end i took apart had .012" movement back and forth at those pinion bearings and the tabs on the lock washer looked like they were only bent over once ( in 1932). so i went and looked at another one i've had for many years without a torque tube on it, so i could easily check it, and it was the same: clearance - not any drag. maybe there is a difference between what the book says it should be - and what really happens during a production assembly ??? unless you want to believe they both could have worn that much.
i found these special thin wrenches in my grandfathers tool box, he was a ford mechanic and service manager from 1923 untill the mid forties. never knew what they were for. untill i started working on my `32 rear axle.

DSC00364.jpg
 
Re: Pinion pre-load numbers?

Bruce listed some pre-load numbers for the A-B pinion that seem a bit high. I used the 15 inch pound for a few jobs and definitely would wonder about the A pinion being a bit tight if bearings that were broken in(however slightly) and generating heat from the load. Worth double checking. Thanks: Fred A
 
I think it got mentioned in another thread, but, it turns out that the OUTER bearing was a press fit on my aftermarket pinion. On old Ford pinions, that bearing is a slip fit. (The pinion I removed from the rear I'm working on had the outer bearing slip right off after I removed the nuts!) I should have used some emery to take the outer end of the pinion shaft down just a little. Then, the outer bearing wouldn't have gone on in jumps and it would have been a lot easier to set the preload.
 
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