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Discussion Starter · #1 ·
How much in-out slop is allowable for OUTER CV joints on REAR axles?

I recently began to notice noise from the rear suspension - right hand (passenger) side. It sounded like a slightly scuffing shoe on concrete, and it was definitely rotational. I checked for scraping fender liner, etc. It only happened when loading up the left and unloading the right while applying power. No noise if the car was not under power. At first it was a little hard to even diagnose which corner it was coming from - but with time the scuffing changed to a knocking noise, still only under moderate or better power in RH corners or exit / entrance ramps.

My car has 185K miles now, about 102K since I bought it four years ago. My online searches indicated I have a classic symptom of right rear axle CV: The UNLOADED axle is more able to 'explore' its freedom to move and bind. The rear axle(s) and bearings are about the only parts of the suspension and drivetrain that I had not touched until now. As of tonight the rear axles and bearings are out - one axle was a beast. And the main bad actor is apparently the REAR RH side (passenger) axle outer CV joint. Unfortunately, while the left side was not making noticeable noise yet, it also has movement in the outer CV joint along the axis of the axle. These are the OUTER CV joints, not the inner ones, which are supposed to move in and out. The boots are all intact, and there is grease in the joints, but I suspect that at 185K miles wear has added up. I have more than a millimeter play on the RH axle, and a bit less on the LH axle. These axles will likely not fall apart any time soon, but it is clearly going to get worse instead of better, and it is not confidence-inspiring.

Can anyone point me to specifications for the allowable axial end movement for REAR outer CV joints on our cars? Lots of posts for front axles, but even a Google search for all brands has only gotten me opinions that there probably should be "no movement" in-out for the outer CV joints. I would really like a tolerance spec, especially so I don't end up with new parts and worry about whether to go ahead and install them or not.

I will probably be looking at rebuilt axles to solve this - But any input before I go there would be appreciated !

Mariner05
 

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Discussion Starter · #3 ·
I have been waiting to post on this until I have things all apart and all back together - but they are all apart, so here is what I found.

The bearings seemed okay, but they were not as stiff as the new ones (if I have to go this far, might as well). The right side axle is here, and the rebuilt one has 'zero' axial play - I just cannot see any at all. The old one has way more than a millimeter, so I clearly have wear going on here. Because the left side axle has similar slop, but not quite as much, I will do that too.

I'll post back results when it's all put back on the road.

Mariner05
 

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Discussion Starter · #4 · (Edited)
Case solved - follow-up: There should really be zero / close to zero slop along the axle direction in the outer CV joints, front or rear. I have finally gotten everything back together. And here***8217;s what was what.

Wheel bearings did not seem to be rough, but at 185K miles they might be rather worn. I had ordered new ones some time ago, and after getting the axles out, the bearings are not that much more work, especially since I have a press. The rear axles were not my only issue: with the car on jack stands and covers off, I saw I had another issue or two. I had checked the front axle boots just 2 weeks before starting this project, but in that time the right front (passenger) outer boot split (maybe by driving through snow drifts ***8211; April blizzard). And when I made a really careful inspection of the left front axle, the inner plunge joint had some pretty bad slop, even though the boots were intact and no grease leak was evident.

I bit the bullet and replaced both front axles together with the rears and the rear wheel bearings. I plan to drive the car another couple of years at about 25K per year, so while a lot of folks would say ***8216;look for another car that doesn***8217;t need any work***8217;, I think my odds are better with the car that I know.

While I waited for axles and a few other bits, I did some other things for long term driving satisfaction: Since the exhaust was down, I replaced ALL the exhaust hanger rubber bits and the cat-to-exhaust gaskets. I also removed the rear differential, took off the rear cover, cleaned it and cleared out the vent, and re-sealed the cover. This gave me a chance to inspect the diff bushings carefully. They were still in remarkably good shape, so I did not replace them. The diff has very slight pinion-to-ring slop, but since it is so slight and the only cure would be a complete rebuild, I will live with it (and mostly not notice, I suspect). Both diffs got new fluid too. One last thing was that I replaced my CSB. I have an aftermarket rear drive shaft, and the new CSB that came on it seemed to spin too freely when installed. It now had acquired visible slop. The new one has no slop, and it's nice and stiff with grease.

Conclusions: My rear axles were definitely worn, BUT they might not have been the biggest cause for my noise / vibrations. The fronts were in much poorer shape than I thought they should be with only 43K and 20 months on them. Although a boot can rip at any mileage, I was especially surprised at the wear on the driver side inner joint with boot undamaged and all the grease still in it (yes, I dissected it, and the grease was still there).

Driving result: My car has never been as smooth and supple feeling in the time that I have owned it. I think many parts wearing over time each contributed ***8211; when there are four of them, the axle noise and vibrations add up, and the CSB was bound to contribute. I don't think anything that I replaced was done needlessly. The rear wheel bearings were the closest call to being "okay". I used reman axles in the rear and GKN***8217;s in the front. (Hope I don***8217;t need to use FCP***8217;s lifetime warranty)

Advice: I hope this can help those deciding what to check for vibration and noise issues. Check and fix front axles first - if I had replaced just the front axles and the CSB I might have been satisfied enough to stop there. Most likely not, since there was that substantial rear outer joint movement. I like my ride again, and hope to make it last a while !

Mariner05
 

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Glad to hear you got it sorted out and shared your findings. Chasing noises can be frustrating especially when your noise doesn't fit the "standard". I went through that with a wheel bearing that would make the same noise whether it was loaded or not.
 
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