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Lubricate rear bearings?

Cliff. Elford

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No emergency , but, how many out there have had experience with using a slide hammer on the rear stub-axel? I do a lot of my own lighter work but this idea makes me wonder if I want to attempt it. The '71 Z in question has 250K miles on it and no indication that the rear bearings have been attended to since it came off the assembly line. I have no noise that I am aware of, the rear end is noisy enough that I can't tell for sure if the rear bearings are in need of help. Am I opening a can of worms attempting to pull these stubs and lubricating them or should I leave well enough alone and continue as they are? Your experiences would be appreciated. Both good and bad.

Gee, a spell checker would be nice. cliff.

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  • 3 weeks later...


im thinking that you are talking about the bearings L and R on the differential itself that support the yoke that that turns the axle shafts. my thought is this: i believe those would be lubricated by the oil in the differential. drain the oil and look for any big metal particles, that many miles would generate some fine particles, to be expected. i dont think you would find anything major since you dont have any slop. if your just gonna cruise around, flush and re-service the diff. if your not satisfied and are a little interested, open the inspection plate on the rear of the diff and check out the moving parts. a book i have gives a procedure to measure and inspect. (Clymer- 240-280z, 1970-1978) these are just to determine if you need to take it in.

If your gonna race, i suppose you would do this anyways depending on the performance you wanted.

in any case i didnt take mine off. but im thinking that the gears would fall if the slide hammer is used then that would be a real can of worms. you might be able to check out the bearings from the inspection plate removal.

if your not talking about these bearings. WHICH ONES ARE THEY?!

just kidding!



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ok i know what your talking about..the wheel bearings...funny Clymer calls it the spindle and Haynes calls it the stub axle.

They do look kinda involved but not impossible. the only thing that you would probably break is a body part trying to take off the wheel bearing locknut. its supposed to be 180- 240 ft-lb torque. ("do-able").

250k is alot. they could at least stand a repacking of grease. if not replacing. there is an inner and and outer bearing for each wheel with a spacer and seals. the outer comes off with the spindle, via the slide hammer, then is pressed off the spindle with an arbor press or somthing suitable. the inner is driven out of the housing. inspect bearings, spindle, housing and spacer for piece of mind replace the bearings...if the spacer looks damaged, replace with the exact same p/n. i think its 'A', 'B', or 'C' and is stamped on the housing. install the bearings back the correct way.

if you havent worked with wheel bearing that much you might want to try front bearings first. they look easier. but i would defintely recommend having a book near by if you havent done them at all. if you have time and patience...go for it...just think what youll feel like when you finish it!..Have i done it? not on the Z but i have done others. what i type here is my interpretation of the book.

by the way, what book do you use?


oh yeah if anyone thinks im giving some bad advice, please give my your input....im no expert and i welcome criticism.

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I use the Haynes book. I have no trouble with the front bearings, that job is no big thing, I just don't like to think of all the trouble and problems that can be caused by misuse of a 15 pound slide hammer. Perhaps I am being too cautious but that is the way I am at times. I think that one day I will pull them and at least force some fresh grease in there if nothing else. Also the experience will be good for me. I have had one lock-nut loose {before descovering I needed a slide hammer} and that was no problem because I used a hydraulic jack on the end of the wrench handle to turn it. I don't know how close to specks I got when I replaced the nut the same way. It is all just a big {expensive too} experiment. The car is fun to drive and I do like working on it. I just don't want to break something really expensive. Chicken me. cliff............By the way, to anyone else reading this,,,I do look forward to any other suggestions or ideas you might have. My email address is supposed to be at the end of this message, You don't have to be afraid of the whole world reading your stuff if you are worried about that.

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Go to the Campfire Stories forum and read "The Stub Axle."

There are two tricky parts about removing the stub axle and both involve removing the nut holding it in. You have to cut off the flats that are peened into the axle before removing the nut. A die-grinder or Dremel with a cut-off wheel is the way to go. Using a chisel tends to damage the threads on the axle.

The second tricky part is getting the nut off. You'll have to generate about 250 ft. lbs. of torque to remove it. An air impact gun helps a lot here. Once the nut is off, you can either use the slide hammer routine or put a brass punch on the back of the axle and pound it out with a hammer.

Inspect the stub axle for cracks or pits around the splines and where the flange is fusion welded to the axle (both sides). If there are any cracks or pits, throw the stub axle away and start searching junk yards. Check the old (and new) bearings while they are in the housing to be sure the outer race does not spin in the housing. It should be a slight press fit. If the outer bearing race spins in the housing (rare), your strut housing is ovaled and is junk. Back to the junkyard.

After 250,000 miles its time to replace the bearings and the seals. Only buy brand new Nissan, Timken, or SKF bearings. Have the outer pressed on at a machine shop, repack with Mobile 1 or Redline synthetic, and reassemble.

Don't worry about the pre-load measurement listed in the Haynes or Nissan manual. You can't adjust it. Just be sure to use the correct spacer and also be sure to put the axle, spacer, and companion flange back in the side of the car they came off.

Good luck!

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Thank you, Mr C. for all the information. I am surprised that the Haynes Manuel does not mention the preened flats. I can only say to them, Thanks a lot. The one time I had one of those nuts loose I made no effort to remove it all the way and therefore did not notice that the preening existed. There is also an off chance that the bearings have been serviced in the past and some one else did that work before me. I can only hope that is true. The original owner was a Datsun mechanic and he owned the car until about 1989 when my daughter purchased it. Perhaps he did service those rear bearings. In any case you have renewed my confidence in myself enough to take on the job one of these cooler winter days. If I find the preening does not exist I will rent a slide hammer and have a go at it. Thanks a lot, Partner. cliff

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  • 1 month later...

I'm doing this very same job. I ended up disassembling my strut assembly. Took out the spindle pin (that was a task). Those were frozen solid. Pressed them out using a hydraulic press at work. If you get the strut assembly out you can bring them to a machine shop to press them out. I had to cut them first to remove them from the control arm. Ordered new ones as well as the locking bolt.

Because it was easier I also used the press to remove the inner bearing (I tried with a brass drift to knock it out but it didn't go too easy, figured I'd use the press since it was available. The outer defenetly used a bearing puller and press combination. It made the whole job easier. I am bead blasting the trut assembly down to bare metal and will be repainting it. I started doing this all because I am doing the rear disk brake swap using 82-83 280zx setup. The backing plate which holds the drum assembly has to come off and is replaced with an early Maxima bracket.

Check your struts at this point as well and replace if necessary. Also the bump stop and spring seat spacer.

good luck and have fun. When replacing the bearing press against the inner bearing housing not the outer. (Good tip from Wick Humble " How to Restore your Datsun Z".

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Originally posted by Cliff. Elford

Thank you, Mr C. for all the information. I am surprised that the Haynes Manuel does not mention the preened flats. I can only say to them, Thanks a lot.


When working on a Z, it's best to have at least 3 manuals lying around. I've had many situations where one manual conpensates for anothers lack of information. And, it's also a good way to verify that the information contained within the manual is correct. I seem to remember shearing a bolt because of an incorrect torque parameter. I consulted another manual and found out that my original setting was off ....

Haynes, Chiltons, Nissan Shop Manual, and of course, the Zcar Microfiche CD!

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I would say that, since it's a difficult job and it may not need doing, find out first what shape your bearings are in. I've never heard of these failing or wearing out, and it may be one of those parts thats built to such overkill standards that it'll last the life of the car. Heck, the factory service manual says to lube the halfshaft splines regularly. What? I've never heard from anyone who does this at all. Doesn't help that it looks difficult to do.

Anyhow, to find out if your bearings are going away, just do as you would for front-wheel bearings. Grab both sides of the tire and try to wiggle it in and out to check for movement. If there's no clicking of looseness, disconnect the halfshaft from each wheel by removing the four bolts, then spin the wheel with your hand. If it sounds smooth with no grinding noise, your bearings are probably fine.


'72 240 since 88

'71 510 1974-2001

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  • 2 weeks later...

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