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Shim pinion bearing race instead of pinion.

jimmydaux

jimmydaux

NAXJA Forum User
Location
Centerville, Utah
Is there any reason why I shouldnt shim a pinion race on the C8.25? When I pulled a purchased axle apart to add new bearings, it didnt have any shims on the pinion. Because of this, I reinstalled the new bearing with no shims. If when I put it back together it has an undesirable pinion depth, I would like to shim the race instead of trying to separate the bearing from the pinion. Thoughts? Warnings? Validations?

Your input would be greatly apprecitated.

THanks All!

JEremy
 
Haven't Been inside a 8.25 axle yet but Dana axles shim the race so from that aspect I don't see why it wouldn't work. Sourcing shims might be the hardest part don't know though
 
The pinion shims are between the outer race/inner bearing and the housing on the 8.25

You need to make you some set-up bearings by honing the inner race so that it can slip on/off the pinion easily. I also have a outer race ground so that I can slip it in/out of the housing easily to change shims. Then you can go from there and set your pinion depth. I do this on the 8.25 by using the pinion depth marking on the pinion head as a starting point and using my pinion depth gauge, set it to that spec. Then install the outer pinion bearing WITHOUT the crush sleeve by bringing the nut down snug but not tight. The pinion should still move and be close to pre-load spec for set-up purposes.

Then you can run a pattern and fine tune your pinion depth. Its an art, not a science. The more you do the better you will get at it!

They make a crush sleeve eliminator for the 8.25, I run it on two of my rears with no issues. Makes yoke replacement on the trail much easier.

http://ratech.stores.yahoo.net/ch8axpa.html
 
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I don't think you would want to shim the race. There should be numbers etched into the pinion gear on the head. That is a reference number and then you can reference that number to the new pinion and then start from there. If you can't read it (my problem). Then you get a bearing splitter or a clam shell and you can separate the new bearing from the pinion making sure the splitter doesn't contact the cage and insert your shim to correct the depth. Also following the above instructions about the crush washer.

When you are doing the lash on the carrier you will need a 36 mm nut welded onto a pipe with another nut on the other end. This will insert through the axle into the adjuster to set preload on the carrier bearings.
 
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jimmydaux said:
I would like to shim the race instead of trying to separate the bearing from the pinion. Thoughts? Warnings? Validations?
Click to expand...
No reason you couldn't shim the race. As mentioned above, finding the shims might be a challenge. I've seen shims under races on both pinion and side bearings. It's probably a little easier to remove/reinstall a race without damage then the pinion bearing, unless you have the correct puller. If you have a good puller, the bearings slip right off.
 
xjtrailrider said:
The pinion shims are between the outer race/inner bearing and the housing on the 8.25

You need to make you some set-up bearings by honing the inner race so that it can slip on/off the pinion easily. I also have a outer race ground so that I can slip it in/out of the housing easily to change shims. Then you can go from there and set your pinion depth. I do this on the 8.25 by using the pinion depth marking on the pinion head as a starting point and using my pinion depth gauge, set it to that spec. Then install the outer pinion bearing WITHOUT the crush sleeve by bringing the nut down snug but not tight. The pinion should still move and be close to pre-load spec for set-up purposes.

Then you can run a pattern and fine tune your pinion depth. Its an art, not a science. The more you do the better you will get at it!

They make a crush sleeve eliminator for the 8.25, I run it on two of my rears with no issues. Makes yoke replacement on the trail much easier.

http://ratech.stores.yahoo.net/ch8axpa.html
Click to expand...

I just did my gears a month ago, the pinion shim on the 8.25 was where it should be, between the larger pinion bearing and the pinion. The HP D30 had the pinion shim between the large pinion bearing outer race and the diff housing.

If your just replacing bearings not much should change for pinion depth, adjust your ring gear backlash into spec and run a pattern. Chances are if you shim the outter race you'll damage the shims when you punch the race out. As suggested buy or make a set up bearing for the pinion and adjust pinion depth properly.
 
Since it came a apart with no shims, Im going to put it back together as such and see how the pattern fares. If It is unacceptable, I will look into pulling the bearing and getting a setup bearing. THanks for the advice everyone
 
I believe it would actually be better to shim the bearing cup. Why? Increasing the distance between the bearing and the head of the pinion actually increases the lever arm on the head of the pinion ever so slightly. OK, this is really negligible but it does make a difference. Either way you need a setup part (bearing or race). There are companies who make pre-manufactured setup bearings and races but they are expensive. I use a high speed drill press and a drum sander to make setup parts.
 
Honestly, like I posted earlier, every 8,25 that I have torn down and rebuilt has been shimmed between the outer race and the housing and that is how I build them back. I always use YUKON master install kits and they come with that size shim assortment for the pinion depth
 
I feared that it wouldnt be accurate by putting it together shim-less, but thought it was worth a shot. There was no shim in it when I pulled it apart, so thought they knew what they were doing. THe pinion nut came loose with barely any torque as well, and then I found out that the crush sleeve wasnt even fully crushed either. THe nut should have been a pretty good sign that they didnt know what they were doing.

Anyone have a setup bearing theyd let me borrow? :)

I put it all together and set it all up and ended up with a less than desirable pattern.

So here are the patterns I came up with:

Drive side:

IMAG0244.jpg


Coast Side:
IMAG0245.jpg


Any of you gear gurus have a really good guess as to how thick I should shim this? I would really like to only have to make the adjustment once. I will, of course, adjust it until its correct.
 
jimmydaux said:
I would really like to only have to make the adjustment once.
Click to expand...

:laugh: Not to sound like an ass but... good luck with that.

I'm still new to gears, I'm in the process of setting up my second set right now actually... But I would do .020" increments until you go to deep. Then work between the thickest shim stack that was to shallow and the shim stack that made it too deep.
 
Ha ha monster,,,, you ass.... ;)

My statement was not ignorant as I assumed that I would have to give it a couple of go's. I would just like to minimize the amount of times I have to break it down if there is someone with a keen eye for these things. A guy can dream, cant he??? :)
 
Hard to say about how much your want. I used the shim it came with maybe if I can recall .035? But what I would suggest if you can't find setup bearings then you can use a splitter to separate it. Do you have the correct tool to adjust the carrier left to right? And know the specs that you need to set preload or what?
 
Yeah, I built the tool for the side adjusters and I am comfortable setting the backlash and preload on those. I just wish I had a press and a bearing seperator. I just need to find access to those..... Challenge accepted!
 
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