Well I apparently screwed up this time. I replaced the pinion seal (12 bolt) just before starting a restoration a year ago. I didn't have an inch pound torque wrench (have one now) and forgot to mark the pinion nut position. DOH! Just like others said, the pinion bearing is now loose (nut tight) and r&p making noise. I'm going to replace the r&p and all bearings this winter. I've done it before many years ago and I have the service manual. I don't have a pinion depth setting gauge and am not going to spend big bucks to buy one. Before, I relied on the gear tooth pattern to confirm the pinion gear was at the right depth. This can be a pain if it's not. Press off bearing, change shims, new crush sleeve, etc. Is there any other way to check pinion depth? I have a dial indicator and magnetic base. von

Von, this is what I did. If you can borrow a depth mic,"it's a micrometer for measuring the depth of holes." I got a piece of flat steel of uniform thickness long enough to go diagnal across the bearing cap mounting surfaces and drilled a hole in the middle to let the stem of the mic go through. Take a measurment to the pinion then subtract the thichness of your bar and you have your pinion depth. If you need anymore info fill free to E-mail me direct. I'll be glad to help. Rick.

I got away scot free a couple of times by marking the pinion nut. Sorry you had trouble.

You might want to consider taking a rear pinion bearing and honing the inside diameter to eliminate all the press on / press off work. Enlarge the hole till you can just tap the pinion and the bearing together by hand.

This does waste a pioion bearing but consider that you might wreck a bearing pressing it on and off and on and off or you might get tired of the process and sorta wing the set up rather than running out to press / unpress perss / unpress the bearing with different shim combos.

Doesn't eliminate all the assy / dis-assy but at least you only need a press when you are doing the final / finish assembly. Using the method outlined above for measuring the depth and rigging a bearing as I outline this job might not be such a pain in the ass.

PATIENCE PATIENCE PATIENCE when doing this job.

I have done this the way Rick above described. Works good. Another way might be to use the depth end of a caliper. Just be sure to subtract the thickness of the plate.

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Much of the above is good advice/info. I have done many of the OLD style Chev rears (similar to 9in with the side adjusting nuts), and one of the things I do on ALL pinions before assembly is to use a peice of emery cloth and work the rear bearing surface until the rear bearing is ALMOST a slip fit. This makes it much easier to install/remove the rear bearing. Even with a depth gauge, the very best way to tell if you have the R/P setup right is by the gear tooth pattern.

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Tom Parsons

Thanks for the advice guys. I don't have a depth mike but do have a fixture to check deck heights with the dial indicator. What I think I'll try is using the flat bar stock across the bearing cap surfaces with a hole in line with the back of the pinion gear. I'll use a steel rod cut to a usable length going thru the hole (close fit to maintain alignment), measure with the dial gauge, add the length of the rod, and subtract the thickness of the plate. I know this won't be dead accurate due to tolerance stack, etc., but should get in the ballpark. Then use the gear contact pattern to verify or fine tune. I'll emery cloth the rear bearing to make it an easier press. No way around using up a crush sleeve though if it's not right on the first time, right? Also have to fab a yoke fixture to loosen/ tighten pinion nut. Thanks again. von

If you are just changing bearings, you will not need to do anything with pinion depth. It will not change the pattern. Just use the original shim.

Just re-read your post and see you are changing gears also. So even so, you can sometimes get away with using the stock shim. At the driveline shop I work at, we use the pattern to determine what shim to use. We have a bearing that has been modified to slide on, with no pressing, as mentioned above, and then we check the pattern, and adjust until it is good, then press the new bearing on, new crush sleeve, etc. It works very well and saves a lot of time. When you put the parts together, keep the crush sleeve and the pinion seal on thew workbench, and tighten the pinion nut until there is a littler drag on it. Without a crush sleeve in there, be careful not to tighten too much and ruin the bearings. After you have a good pattern, then use the new bearing & new crush sleeve and install the pinion seal.
Good luck.

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70 & 1/2 RS Camaro
SB406 & M20 4spd
9" Rear
70 Malibu
SB350 & TH400

Gold Member # 103




[This message has been edited by Scooter (edited 10-31-99).]

As long as you are using a G.M. ring and pinion, you can reuse the original shim. After putting together over 100 ring and pinions sets in Chevys, I can tell you that the original shim works with a new bearing set also.But if you have run with the loose pinion gear, I would advise you to check the teeth because you have probably damaged them.
As for taking a pattern on G.M. gears, I have never seen any official G.M. repair material addressing that method. Aftermarket gear sets are another thing though.
Tony

Is there any way of replacing the crush sleeve with a machined sleeve that is solid of the correct length?Also I have just purchased a new Richmond gear that did not have the instructions with it,is the pinion depth marked on the pinion gear?I am a machinist and just thought maybe I could machine a sleeve instead of buying more than one crush sleeve.

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John 67SS
ACES #2887
Team Chevelle Gold #127
Bassett,VA

I don't think so. You could get em set up correctly then remove the sleeve and make one up but why would you wnat to go to the added trouble. One the gars are done I would not want to take them apart.

The length of the sleeve crush is determined as a bi-product of setting the perload. Once it is done it is done. I suppose if you did finish the set up, take the rear appart and make your own sleeve using the "template" you would have a ready made sleeve for the next time. That sleeve would only be useable IF you ever had to remove and re assemble the same ring and piion in the same rear.

Can't you use the old crush sleeve to check the new gearset pattern, and then once you get the pattern and backlash set, put in the new sleeve?? Or will the pinion preload setting change the pattern??

Set the gears up with out the crush sleeve first, then after everything is set up, install the crush sleeve and pinion seal. There is absolutely no sense in putting in a new crush sleeve until you have everything else set. If it's that difficult to do, take it to a professional shop and have them do it and eliminate the headache. I do GM diff's everyday, and it's really not that difficult if you know what you're doing. For the average auto owner, I'd recommend taking it into a driveline shop and have it done right.

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70 & 1/2 RS Camaro
SB406 & M20 4spd
9" Rear
70 Malibu
SB350 & TH400

Gold Member # 103

Scooter, Thanks for your help. I've done this before, but it's been 20 some years. I have the '69 service and overhaul manuals. I'm determined to do it myself. It will be a couple months before I tackle it. If I hit a snag, I'll Email you if that's OK. von

Von:
Not a problem. You can e-mail me anytime.

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70 & 1/2 RS Camaro
SB406 & M20 4spd
9" Rear
70 Malibu
SB350 & TH400

Gold Member # 103

The flat plate method isn't always the best way, as the measurement is from the center of the axle bore to the indicated place on the pinion butt. When a shop uses a pinion setter, they use a pair of round inserts that replicate the axle centers, then a bar with a flat cut into it is used for the distance measurement. If the bore is offset in the carrier, then the cap/carrier cut isn't in the axle center, and the pinion depth won't be read correctly.

To use the flat plate measure method, check both the carrier and cap cuts for the same depth from the mating faces, and adjust for any offset. Add/subtract the distance from the proper pinion depth, and it will come out just fine.

Cutting the pinion bearing register od is much easier to do than getting the id of the bearing recentered for slip fit of the rear bearing. I use the slip fit and Lock-Tite method, without any problems.

I set my preload on new bearings at 17/22 in/lbs, used at 15/18 in/lbs.

I never use synthetic gear lubes, always use posi additives for posi, and always, always use 140 wgt gear oil, no lighter. Works for me.