Pinion Bearing Preload

[Brent13]

All,

Changing R&P in the 9". And ready to set pinion preload. One slight problem, the new bearings are obviously a press fit onto the pinion shaft. Well, if I don't get the spacer correct the first time, I will have to pull the bearing off to change shim stack. I never get that lucky the first time. Anyway, just so happens that the old pinion bearing does slide onto the new pinion shaft. Can I use the old bearing to set pinion bearing preload? Is this acceptable? If so, once I get it right. Will disassemble, remove old bearing, replace with new bearing, and drawing new bearing on with the pinion nut. Sound like a good plan?

Thank you

 

[NC-Fordguy]

Yes, double check your preload after the new bearing is installed. New bearings will have less wear so you may get a different read. If so, remove pinion nut and yoke and tap the pinion out with a brass hammer and readjust your shim count.

 

[Brent13]

Ok, just worried about pressing on and pulling off new bearing more than needed. Afraid the new bearing is going to be awfully tight on the pinion shaft and require monumental effort to pull off, if needed. This is my first time doing R&P swap, so I am not counting on getting the spacer correct the first time! I am using the solid spacer from Tom's, and even without shims, it is .008 taller than the crush sleeve I removed.

Thank you

 

[Bferrari]

The new bearing will come off, I use a dead blow hammer to tap the end of the pinion. You can use your old bearing to get in the ballpark, however make sure you got the 20 in pounds of drag on the shaft when you are complete. On a 9" I don't bother with a setup bearing (I.e. Your old bearing). I do however use them on the 44 and gm corporate setups.

 

[broncodriver99]

The new bearing will come off, I use a dead blow hammer to tap the end of the pinion. You can use your old bearing to get in the ballpark, however make sure you got the 20 in pounds of drag on the shaft when you are complete. On a 9" I don't bother with a setup bearing (I.e. Your old bearing). I do however use them on the 44 and gm corporate setups.

X2. The Bearing that goes next to the gear is a tight press fit but doesn't need to come off. The one on the yoke side is snug but can be removed without too much trouble. Just remember to set your preload without the seal installed.

 

[Brent13]

Well attempt #1 is no good. Locked up tight at only about 80 foot pounds, and I am using the new bearing. So now I need to take apart and add shims. What is the trick to getting the yoke off?

 

[Quick & Dirty]

When setting up a solid spacer, always start the shim stack too big and work your way down. Putting a 200 ft-lbs nut on an unsupported bearing can damage it.

80 probably didn't hurt it, but go bigger than you'll need with the shims for the next go round.

 

[Brent13]

Still need to verify my pinion preload, but think I a pretty close. Need to buy or rent an inch pound torque wrench. Found an issue, appears my third member housing pinion bearing support is interfering with ring gear. I have read that that can be an issue, and will need to take a die grinder to it. Will get a look at it tomorrow, see how much material needs to be removed.

 

[Bferrari]

Still need to verify my pinion preload, but think I a pretty close. Need to buy or rent an inch pound torque wrench. Found an issue, appears my third member housing pinion bearing support is interfering with ring gear. I have read that that can be an issue, and will need to take a die grinder to it. Will get a look at it tomorrow, see how much material needs to be removed.

Yep, had to grind the crap out of mine with 4.88's



Use your existing pinion shim to begin and try setting your backlash. Pinion depth will affect the placement of your ring in the carrier but the existing shim is a good place to start for clearancing your pinion bearing support. Free up enough to check a pattern (validate your pinion depth) and go from there.

 

[Apogee]

I had to grind mine with 4.88's as well...no big deal.

As for the pinion preload, I just used the press instead of the pinion nut to preload the assembly and measure the preload since I was using a solid spacer, that way I wasn't dealing with the yoke and spindle nut at all. Worked well and made things much quicker.

 

[Brent13]

Ok, got my wrench today. I have achieved 20 inch pounds of bearing preload at 175 foot pounds on the nut. Is this acceptable? 20 inch pounds feels tighter than I would have imagined. The You Tube video I had been watching to perform this job recommended 25 inch pounds. I am installing new bearings, and using a two piece TBP solid spacer with one .008 shim.

Thank you

 

[NC-Fordguy]

20 sounds a little too tight. 15 would be better. IIRC 175 foot pounds sounds about right on the pinion nut

 

[Brent13]

It does feel flipping tight, and will get a bit tighter with the seal, correct? Need to see if I have an appropriate shim. Don't think I do. With a .005, it locked up. With .010, I had less than 5 inch pounds. Right now i am at .008. Based in that, the math just doesn't seem right.

 

[Bferrari]

It does feel flipping tight, and will get a bit tighter with the seal, correct? Need to see if I have an appropriate shim. Don't think I do. With a .005, it locked up. With .010, I had less than 5 inch pounds. Right now i am at .008. Based in that, the math just doesn't seem right.

The seal doesn't make it tighter. If you are at 20 inch pounds of drag with your 8 thousands shim, run it, you are fine. Your math is correct, less shim, closer the bearings, equals more drag (.005 locking up). More shim, more space between bearings equals less drag (.010 with less than 5 lbs.). Your .008 is in the sweet spot, 20 in pounds is right on the mark.

 

[Apogee]

20 in-lb sounds right there in the thick of it...I'd run it. FWIW, new bearings should be set up tighter than used bearings, since they'll loosen up as they wear in. I've always used 12-15 in-lb for used and 18-25 in-lb for new bearings.

 

[Brent13]

Thank you, checked again, I was at 15 inch pounds, I am going with it. Mounted up the carrier, set some preload on the bearings. Adjust backlash to about .008, gear set calls for between .007 and .009. My pinion depth is a measure 1.023" and marked as such in the pinion. Pinion shim is a .016. This is my first time doing R&P, getting late, and I just had to try a pattern, so here it is. How's it look?

 

[broncodriver99]

That looks pretty damn good! How's the coast side? Perfect would be slightly lower on the ring gear but you are definitely in the completely acceptable stop f***ing with it range. Your are loading the ring gear right? Broom stick works well. The pattern will move a little under load but you look to be in a pretty good spot.

Now try to get that on your D44 first shot. Not gonna happen.

 

[Brent13]

If I remember, the coast side was a bit lower. I am still looking for another set of eyes on this before I put it back in. I don't want this thing to grenade!!! I will be tearing into the front end in about a month. I have been down for well over a month with the rear end work, I need some driving time.....

 

[broncodriver99]

Here is some info that I found handy when rebuilding mine. There is some good pattern info. http://www.sierragear.com/differential-installation-setup-instructions/

 

[Brent13]

Folks, can I get one more pattern check opinion? I was not confident with carrier bearing preload, so I tore back down, put back together and set backlash back to .007. Ran another pattern, drive and coast shown.




Thank you