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I replaced the left rear wheel bearing at about 147k with a bunch of advice here. First time I ever had to do an actual bearing replacement, prior experience having been strictly integrated bearing/hub swaps. Took some doing, wasn't entirely satisfied with my results initially (it worked and was tight, but after assembly I couldn't spin the wheel by hand until I drove it, then all seemed good). Confident that I reassembled everything in the right order. The original axle nut seemed like it wasn't in tight enough as it came off with almost no effort on my impact and the threads were not distorted at all.
Growling came back about 5-6 months later (roughly 9000 miles), inner bearing and seal had self-destructed. I assumed it was my process, but could have been a bad part mixed with some bad luck. Pulled it all apart again, removed the bad parts, new inner bearing, race and seal. Everything went back together nice and smoothly, confidence level was much higher and after I reassembled I was able to spin the wheel freely by hand, so I figured I did a better job.
Not so fast there cowboy. Noticed yesterday after maybe 3000 miles that the growling is back. Checked all 4 wheels, it seems to be the left rear again. It isn't wobbly at all apart from a slight 12 & 6 wiggle which I believe is either normal (both sides do it equally) or indicates I need to do the fulcrum at some point in the future. Left rear wheel spins, but not freely, it stops spinning as soon as I take my hands off it, its like the brake is dragging slightly, but there is no sound like it is. I see no evidence of uneven tire wear anywhere on the car, still tracks straight too.
So I'm skeptical its the part quality. Once ok, but not a second time, this time I used a Timken bearing. I think my process is ok, but willing to accept its not. Everything fit together nicely and it all just felt right. I think I used enough grease, got like a half a tub in there between the roller bearing parts and just packed inside around the hub, collar, spacer and all that. I thought maybe I under greased the first time, so I erred on the side of over greasing this time.
Tonight I figured I'll get out my inspection camera and see if I can get a good look at the state of the inner seal and/or bearing condition. The last time the whole seal basically was destroyed and the inner bearing came apart, so maybe I'll see some obvious damage there. I can also remove the axle nut and just pivot the carrier out and I can examine it all directly for damage, which will also let me spin the hub without the differential being a factor, which would eliminate the differential output bearing (or point me at it I suppose, which is also possible. I have a spare axle nut so I can do this once without much trouble.
Interestingly, despite having installed it to torque spec when I did the job the first time, the axle nut came right out without any damage, which I figured indicated that I messed up as I believe the threads on the nut are supposed to self-destruct. Something tells me that the second time I did this, even though I went to the 306nM of torque (or whatever the spec is, I know I looked it up and had to buy a new torque wrench to go high enough) that the nut still isn't distorted as I don't recall hearing or feeling a crunch, but I don't know if I would.
Assuming for a moment that the inner bearing has indeed once again failed on me, any thoughts what might be causing this? I checked the prop shaft u-joints and they seemed snug to me, no rotational play that I could feel and they are definitely greased. Both times I've done this job with the carrier on the car and attached at the fulcrum, never loosened it or anything, is it possibly I didn't snug it all up properly? I would think that by torqueing the axle nut to spec, that this would not be possible, but maybe? Maybe I'm just not doing the axle nut correctly in the first place since its come off twice with no thread deformation (installed once by a prior owner, once by me with no damage, once unknown as I haven't removed it yet). I can say that I did not use anything on the axle threads like anti-seize or anything that might have lubricated it unintentionally.
Ideas? I'm getting tired of replacing bearings...though the practice is certainly making the job go more quickly. Tempted to pick up a whole new carrier with hub assy from ebay, but if an external factor is the problem, this'll just keep happening, right?
Haven't pulled the wheel off yet to check the axle nut, will be doing that tonight. If it is loose, it begs the question of what on earth did I do wrong, now twice.
Yep, seems to be the wheel bearing is gone again, or going anyway.
Got the wheel off the ground, still turns stiffly, almost can't turn it by hand without the tire on there for leverage. Tried a basic eyeball inspection and I see nothing out of place like I did the last time. Checked the torque on the axle nut and it was still at the low end of the 304-336nM (my torque wrench was still at the 226ft-lb I set it to when I did this the last time. Located my spare axle nut first and then opted to remove the axle nut for a better inspection and get the propshaft out of the equation as a possible factor...wouldn't you know it, the axle nut did come right off with my impact and again the threads appear to be fully intact, I see no deformation anywhere inside the nut, nothing left on the axle that resembles a helicoil or anything...I'm stumped by this and I'm kind of getting hung up on it being a factor in my issues since its not behaving as it should. I'll discard this old nut and use the new one when I reassemble and make sure to degrease, clean and dry the axle threads first.
Freed of the axle I can spin the hub by hand and I can clearly hear what sounds to me like some bearing issues, but I've uploaded a video to youtube just in case someone wants to tell me otherwise. Can't see anything past the hub and ABS ring until I disassemble it, I'll get photos as I disassemble and maybe it'll become clear what I've done wrong so I can at least learn from this and stop wrecking perfectly good bearings.
I'm guessing that despite my best efforts that something has perhaps gotten in there and contaminated one or both of the rollers. I'll order up a set of bearings, races and seals today and hopefully get this knocked out over the weekend.
If you're worried about the axle nuts backing off, put witness marks on them so you can see any movement/loosening.
Play at only 12/6 is likely to be in the U joints or diff output shaft bearing. I suppose it could be the pivot bearings but that would be pretty bad wear in them at that point... when the whole system is assembled you can test this by having a helper rock the wheel at 12/6 and feeling, or looking for play at each of those potential points of wear. Or, when you have the bearing out, you can test each part (hub pivot, halfshaft + diff bearing) independently, although it's harder to get leverage on parts in this state.
I've not done the job but it sounds like it's a single use nut holding the hub on? if you're not replacing that (as it sounds like you aren't) then it'll come loose, as they are designed to work once.
A few years back (3ish?) there was one of our members who had one of the rear wheels, entire bearings and races replaced BUT, the axle nut *wasn’t* replaced. He picked it up from the shop and on his way home he took a turn, the rear wheel including the caliper, rotor and the outer hub laid down (12 o’clock position of wheel touched the ground), lost control and ended almost upside down in a ditch. Car was totaled and I *think* he was ok for the most part. Oh btw, it was a 99’ Supercharged Vanden Plas (RARE) the blueish/purple colored one. The old axle nut came apart and caused the accident when it was investigated. He bought the totaled car from the insurance company and parted it out. I bought the body badges from him and other parts as well. The moral of the story is that you should replace the axle nut with a new one every time it comes off.
Yep, seems to be the wheel bearing is gone again, or going anyway.
Since you did not mention that you followed the procedure described in the Workshop Manual, I attach the relevant extract (just in case). I haven't done this work, it seems rather complex.
Thanks for the procedure! Maybe this will help me find the problem.
To be clear, the first time i did this, I found the original axle nut had not been put on tight enough, or had worked itself out, no way to know...but its threads were clean and true, nothing was distorted at all, so at the time I concluded that it might not have been put on to spec because these nuts are supposed to self destruct at 224ft-lb. I discarded that nut, did the bearing change and installed a new nut torqued to 226ft-lb. The inner bearing for that job self destructed, rollers were falling out when i took off the abs reluctor...the axle nut i removed that time (that was new from Welsh) was completely undamaged, based on the other threads I read about these nuts i expected to see deformed threads inside the nut, or helicoil-like bits left on the axle shaft. The nut is completely undamaged and screws on and off smoothly...its weird. When i re-replaced the inner bearing, race and seal, I opted to reuse this axle nut.
Now about 3000 miles later, the bearing is starting to make noise again, first thing I did was check the axle nut torque, my wrench still shows 226ft-lb on the nut without it moving, so I'm pretty confident it hasnt backed out at all.
I have a new nut to use when I do this again, but i'm really wondering why these things aren't distorting like they're supposed to. While this bothers me, I'm not convinced its the source of the problem either as its not loosening, but I'm 100% happy to learn why it might be. Since the torque spec is a high/low, I've been using the low since its not a new axle and it doesn't make much sense to me to have a high new part rating and a low reused part rating on a single use nut...maybe I should go to the high rating when i reassemble this time?
...but its threads were clean and true, nothing was distorted at all, so at the time I concluded that it might not have been put on to spec because these nuts are supposed to self destruct at 224ft-lb.?
Where did you get the above described info? It is completely wrong. The "helicoil-like bits" on the thread could only be pieces of hardened Loctite. The manual does not state that the axle shaft nut should be replaced, only that Loctite 270 (Red) should be used on it. What almost always needs to be replaced is the bearing shim. What is important here is that, with the selected correct shim (sitting next to the spacer) and when the axle nut is tightened, you have a 0.076 mm end-float of the bearings. This means that the force of the tightened axle nut is taken by the spacer and the shim and not by the bearings. If you follow the instructions about installation of the bearings, step by step, everything should be fine.
It is likely that earlier you did not have correct shim which caused the bearings to be in a pre-loaded state (instead of having a small end-float, clearance) which caused the bearings to fail. The wear of the bearing under the pressure from the axle nut caused the nut to loosen out.
The info above was what I got out of reading other, older threads on this forum, like the one linked here. I have seen over and over again, the inserts seeming to come out when people remove the rear axle nut and people really hammering home that the axle nut is a one time use, even Welsh Parts said it when I ordered my original set of bearings, so I've been going by that. Reading other threads was also where I got the idea that the shims should be reusable since at least in theory, none of the distances have changed from the original factory setting.
I've got the procedure you kindly sent and I'm absorbing it. I have to educate myself on how to do the things described like measuring end float so that this is the last time I end up doing this procedure. Maybe this time I'll just take that whole carrier off and consider changing the fulcrum bearing at the same time since it will all be apart anyway, thus far I have left the carrier on the car and folded it out on the fulcrum to work on the bearing races and have been using a bearing press kit to reinstall all the various bits. my 20 tom vertical press would make some of this easier for sure but I've been hesitant to take off the fulcrum for fear of opening a second can of worms.
I am saying this out of perspective, these cars are over 20+ yrs old. Direction you've seen in the past may not be correct for your current issue, especially on the drive line. So just replacing a part and putting back on the other items is a risk. Everyone should replace all the items possible of specific torque...nut, bearing, shims. You have no idea how much wear may have occurred in those yrs and what may have worn. What the PO's did with the car if anything and how hard they ran it is unknown and your guessing. It should be treated as a completely new install, it's the only way to CYA.
To clarify, are you suggesting replacing the whole carrier/hub assembly with an EBay special and just do the bearing swap on that, per the instructions above or keeping what I have but replacing more than just the bearings, races and axle nut?
Until you pull that bearing, you won't know if it rotated in the case..that's some not so healthy noise. Now it shouldn't have rotated an you should just need to redo the bearing assembly, races and nut, follow what MS said in post #11.. But, it may be out of true and causing early bearing wear or simply just had been a bad bearing or improperly shimmed as noted by MS. Thing is, you're there, you spent the time taking it down and it went bad quick for a reason, better to err on the side of caution. If you or a local shop can check it for true is where you have to start.
There may be a great deal of wear on the parts. Especially so if an install
was not correctly assembled or toleranced. It is very important that the shim
and spacer are installed as M. Stojanovic suggested.
So the end float is how much the hub moves in and out of the carrier with all the bearings, spacers, seals and abs ring installed, but without the axle or axle nut installed. Since .076mm is such a small amount, is it safe to assume that this is difficult, if not impossible, to do without a proper gauge, which I do not own? I'm not convinced I could even feel that end play by hand for example.
If my existing shim has been compressed slightly over time, or was perhaps swapped out by a prior owner from the original, then my end play would be too tight or possibly non-existent, correct? If I needed to add shim space, where would I go to get the right shim? I haven't seen a shim kit for sale yet, but nor have I searched aggressively.
I suppose I'll keep an eye open for anyone parting out an X308, maybe they'll make a deal on the left rear carrier. Are they different XJ8 to XJR or between early cars and later cars or are all X308 rear carriers the same?
The shims are sold by piece in various thicknesses in small increments (a complete set would cost you more than $700). You need to buy the thickest of the shims and measure the end float with it following the procedure in the manual. Then, you calculate the difference between the measured end float and 0.076mm and you then order the shim which is thinner than the thickest shim by the said difference.
I would measure end float with something like the following? It measures thousandths of an inch, but if my math is correct, I need almost exactly 3 one-thousandths of an inch here (2.992 thousandths)
03-12-2024, 07:56 AM
Rear Bearing Repetitive Woes
