Finally rebuilding my 7.5

[Bonnewagon]

Oh, I get it. You measured the old crush collar that was already preloaded properly. Then removed it and substituted a solid one, same size, and then matched the preload . Gotcha. Is there a reason to do that? I've never heard of a crush collar going bad, unless it was tightened down too much. Then it must be discarded and done all over again.

 

[pontiacgp]

I measured my existing pinion depth and matched it with the shims that come with the solid spacer when I did my gear swap. You can use the special holding tool and an inch pound torque wrench. I used an impact and set it where it had no slop but no resistance turning it.

there needs to be some resistance turning the pinion, with used bearings it's 10-15 inch pounds and with new bearings 20-25 inch pounds.

 

[Bonnewagon]

Right, that's pre-load. As the pinion nut is tightened, the collar crushes, until the pre-load on the bearing is at specs. Pre-load being the inch pounds of force needed to turn the pinion with no load at all meaning no brakes, just bearings. I guess you could then remove the crush collar, measure it, and replace with a solid one, and put it back exactly the same way so the pre-load is the same. This is how you change the pinion seal without mucking things up- you measure the exposed threads and pre-load, change the seal, and replace everything exactly as you found it. But, why would you need a solid one once the crush collar is set properly?

 

[onebadasscutlass]

Ok I got the gear. Still the wrong one but I cut my loss and it going in should have some update s and pictures soon. I can't wait

 

[olds307 and 403]

I would bet I am very close to the spec, 15 inch pounds is diddly. The crush sleeve sometimes doesn't crush plus the solid spacer is stronger. Anything to help this flimsy rear. I have done the 7.5" with proper tools before in a shop, so I what is right for preload and backlash. Only failure I have had is a no slip break the pins and the spider gears explode, took out the pinion. Multiple runs on slicks and no noise at all. Either a Tru Trac or Detroit locker is going in for a posi.

 

[pontiacgp]

I have never seen a crush sleeve that did not crush...and 15 inch lbs is an important measurement

 

[klaird]

Question...Decided to post here rather than starting a new thread. Now that I got the rear wheel bearings figured out and squared away, I am noticing more play than I would like in the pinion bearing (the pinion seal is also leaking). I've got the darned thing all apart I might as well replace the pinion bearing while I'm at it!!! So, If I remove the carrier and expose the pinion gear, I should be able to drive out the pinion gear and drive out the old bearing(s). My question relates to crush...Is it more important to match the current crush (if the wear pattern is good showing no sign of tooth wear, or is more important to get the correct book value of 20-25 lbs crush. Is crush tension simply a matter of tightenin the pinion nut tighter if more resistance is needed? All I need to do is replace the pinion bearing and I don't want to replace anything else that doesn't need to be a part of that process. Please direct me to another post if the step by step has already been spelled out - no need to reinvent the wheel on this thread...

 

[crazy87]

your current crush is not what you want seeing that the pinion seal is leaking and it's loose. Crush only effects bearing preload not gear wear pattern. A new crush collar will be loose until you achieve the desired 20in lbs. Old shop trick I used is set up with new bearings and new crush collar, leave new seal out, using old nut(pinion nuts are self locking and are a one time use ) get pre load close, crushing new collar, ( Better reading without drag of new seal on yoke,) now remove old nut, install new seal and new nut. Always refer to a good shop manual as a reference . Good luck I hope this helps.

 

[axld86]

raytech makes a solid spacer you shim to set the pinion depth, you can hone out the inside race of the press on bearing to use as a "checker bearing" . they also make this http://www.summitracing.com/parts/rat-10003, ALWAYS use a new pinion nut . now all that is left to do is shim the carrier for proper back lash/ wear pattern. bolt up the wheel / tire assy. provides the drag needed, and check ( I use a beam style torque wrench )to check the pre-load needed to turn . adjust as needed. i might have over simplified this but I've done this so many times , i might have left out something.

 

[Bonnewagon]

Klaird, while it would seem possible to just change out the outer bearing and seal, what condition is the inside bearing? There are two you know, and both probably should be replaced. That said, the factory manual states that ANY part replacement requires rechecking everything to specs and using a new crush collar. But I would bet that you could get away with changing out BOTH bearings as well as the the races, reuse the stock inner bearing pinion shim (unless it's chewed up), a new crush collar, and reset the pre-load to "new bearing" specs. BUT, changing the bearing races is impossible without the pinion gear coming out, which requires the ring gear carrier to come out, which involves re-installing the stock cast carrier spacers (fragile- do not hammer them in) or a new carrier shim set. Ain't rears fun? But the original idea of just changing the outer bearing seems like the easy way out, but are you comfortable using a new bearing in an old race? Of course you could also just leave the bearings alone, tighten up the pinion nut to "used bearing" specs, add a new seal, and pray all will be well. Pinion pre-load is the inch pounds of torque needed to turn the pinion flange with NO brakes dragging. As you tighten the pinion nut to achieve pre-load, the collar crushes and too much ruins it, you can't loosen and try again, gotta replace it and start over. Do ya feel lucky?