2001 XJR, 156,000 miles.

So over the holiday weekend I swapped out my right front bearing. Its been slowly on its way out for the last few months and it was just time to do it. I figured the slowly increasing growling sound I've been hearing inside the cabin was due to it and was looking forward to a nice quiet ride again. Well the bearing is now new and I still have the noise, so I'm wondering if anyone has some good, methodical testing recommendations so I can properly isolate the noise. Its speed dependent, not rpm, difficult to tell where its coming from, sounds like my left rear wheel bearing sounded like earlier this year, but I checked both back wheels and they both seem pretty solidly in place.

I think there are 5 u-joints in the car, various bearings between the trans output, driveshaft and differential input (I assume) and outputs...but what's a good way to test them so I'm replacing the right thing versus shotgunning parts at my car? I can put it up on jack stands and run it up to 40-50mph or whatever and see if I can isolate the noise.

I believe the noise might be along the length of the driveshaft as it seems to have a bit of slack in it between reverse and drive, so that bears closer examination, how about the differential bearings? I've noticed no real vibrational issues, but the noise seems like a bearing-like growl to me.

For what its worth, the front wheel bearing did need replacing regardless, I had a pretty significant play in every direction on that wheel and there was a minor vibration and tendency to wander on the highway that is now gone, so at least I didn't waste my time.

Thanks!

 

I’d be looking at the rear differential, specifically at the output shafts and UJ joints. These have grease nipples on that more often than not never see a grease gun. Also a while ago with my old 3.2 XJ8 which had 143k miles I had a low growling sound develop from the rear end, I was 500 miles away from home in Belgium at Christmas time when it happened. It got me so paranoid it ruined our trip as I was reluctant to drive the car any distance except home, which itself was a stressful journey on high alert just waiting for a spectacular breakdown.

When I got the car home I got it on a ramp and inspected the rear end where I noticed the driveshafts were showing wear. I greased them via the nipples which helped massively and I was going to change the diff fluid, but I sold the car before I got round to doing that.

 

You could connect a funnel to some cheap rubber tube (about 12mm), cable tie the funnel near one of the bearings, run the tube into the cabin and and hold it to your ear while driving... just keep moving the funnel around til you hear the noise loudly through the hose, now you know the noise is coming from somewhere near the funnel. Super ghetto, but it works! 😂

The modern version of this is probably to use an external microphone on your phone or video camera, and listen to the recording back after a drive...

 

Or if it's easier, use the same trick while the car's on stands

 

With that kind of mileage, slop in the ring and pinion gears is common. Check the diff fluid level next when you go to grease the output shafts then retest. Another potential noise could be the driveshaft center support bearing. I’ve come across the noise on a road test but when I try to replicate it while up on the lift, the sound would go away. I just want you to keep that in mind as I’m not condoning replacing of that center support bearing unless you’ve narrowed it down to that.

 

Thanks guys! Will get it up on jack stands and see about doing some listening. I begin to hear the noise around 30mph and it is audible at any speed I've gone above that, varying in pitch with speed.

When I bought the car last summer I tried to educate myself about the basics and did find the four zerk fittings on the rear driveshafts and have left them greased as best I can, though they haven't been checked recently. There was no noticeable play in the u-joints when I did the rear wheel bearing this past spring. Around that same time I managed to get at the differential drain plug, eventually got it open and while I didn't have the tools handy to siphon the old fluid out, I did top it off with about 1/3 quart of valvoline synthetic gear oil...I can't recall the weight but it was the same stuff that has been recommended repeatedly here...certainly can't hurt it to put in the effort of getting it drained and refilled properly.

I'm also going to remount my summer tires and make sure I'm not being an idiot and have it be my snow tires and their more open tread pattern.

 

Good thought on swapping the summer tires to see if the winter tires are causing the issue. Year ago I rebuilt an entire differential in a Mustang because I swore that's where the noise was coming from. Turns out it was the tires making the noise...Put tires on and noise was gone. I believe one had a shifted belt but it was years ago so don't remember exactly.

 

Bugger.

Definitely not the tires.

Put the back end up in the air, startedstartep and got it up to 30-50 (noise becomes evident while driving around 30). I hear it clearly. Pull off the wheel, repeat, still hear it. Lubed the u-joints on that axle, no different. Pulled off the caliper, carrier bracket and rotor...still making a racket.

So I'm going to go.out on a limb and figure I did a lousy job with the wheel bearing job I performed on that corner this past spring. Only way i can think of to find out for sure is to take it apart, but if I take it apart I might as well be prepared to do the bearing again.

So, now the question is, do I do the bearing again, or does it make any sense to get a replacement hub assembly off ebay and slap it in intact, with the knowledge that that bearing is an unknown age and condition.

Probably more reasonable to just redo the bearing, but what does everyone else think?

 

Steelman Chassis Ears ! These aren't cheap but will save you a huge amount of time in diagnosing running gear noises and problems. I bought a set several years ago and haven't regretted a single dollar of the tool cost.

And yes, they work really well.

https://steelmantools.com/products/w...vice-kit-61082

 

Those are exactly the modern day equivalent of the old fuel line and funnel trick!! That's awesome, thanks for posting that link.. a set might find its way into my workshop soon

 

Yep, that Steelman kit is great. You would be amazed at how sensitive they are, you can hear bearings rotating, diff backlash......all that stuff.

Yes, this is somewhat pricier than 4 funnels and lengths of fuel line but the headset is much easier to manipulate

 

The price is pretty reasonable for what it is, especially if you use it regularly... even so it's one of those things that'd be wonderful to have on hand for that one time a year you need it. I looked for a cheaper alterative using four 12ft corded lapel mics and a USB-powered mixer (links for examples).. that works out to about half the price, but you don't get a case or anything and you don't really get a warranty either! Unless you can use the lapel mics and mixer for something else, I think the kit you posted would be a better buy overall

 

Ordered up a set of timken bearings and races for the rear, will pull it all apart maybe tomorrow evening and see what the damage is inside. Hopefully its just either a defective bearing (unlikely) or just me being a nincompoop and not using enough grease or something...hopefully the hub and shims aren;t damaged in any way and I can get it knocked out and back on the road.

 

+1 on chassis ears, lets you test multiple points simultaneously to really find your noise... they have a wired version if you're looking to save a few $ over the wireless

Now all we need is a similar style pack of wireless inertial measurement units with data logging features, to track down where that damn vibration comes from. That'll really round out diagnostic equipment. High enough bandwidth and they could probably capture bearing vibrations...

 

And wireless chassis cameras, cameras would round out that diagnostic picture, no pun intended

 

Found the source of the noise!



The inner bearing looks to have completely self destructed. Inner seal looks like it tore up some too so I'll have to pick one of those up as well.

So now the important question is why this happened. I suppose its possible it was just a failed bearing, but its also 100% possible I messed up.

The axle nut came off fairly easily with ny cordless impact. The threads do not appear deformed, but I'm confident i torqued it on when i did this bearing job in June, so I don't know what to make of that.

Knocked the inner race out, outer race and bearing look great so I'm not sure there...I suppose its apart and new parts are coming so i might as well knock out the outer race too.

 

Was it a decent make of bearing you used last time?

I ask as I've had bearings from 'all *****' fall apart in a few thousand miles from new in a bike despite being fitted correctly & I'd been told they were a good make.

 

Couldn't tell you the brand of the failed bearing, I purchased a rear wheel bearing set from Welsh Jaguar for $30 and opted to trust that they were selling a good quality part, Replacing with Timken this time, which is a known definite quality brand. Outer bearing had plenty of grease on it, inner bearing I'd say maybe not so much so I'm operating on the assumption this was my error and I just didn't lubricate it adequately. This next round will just use the whole tub of grease because at no time in history has anyone ever said "If only I hadn't used so much grease, my bearing wouldn't have failed".

Should hopefully have the new parts tonight and, barring other life things taking up my time, I should be able to knock it together and see how it goes.

 

So I'm (possibly over-) thinking about this and reading some old threads and the order of the parts between the bearings has me a little befuddled.

When I originally disassembled the hub, I had the thin shim between the big spacer and the outer face of the inner bearing, so thats where I put it when I reinstalled. The diagram that I found online agrees with this placement (see attachment). I'm referring to part #4.

But in some past threads I see this same shim being referenced as being between the outer face of the big spacer and inner face of the outer bearing.

It seems logical that the placement of this shim is important because it will help set the preload of the whole assembly, correct? If it actually belongs up against the outer bearing and I placed it against the inner bearing, then I could see that causing extra pressure on that bearing and potentially causing premature failure. Is it possible that sometimes the shim is on the outside and other times its on the inside and it varies from car to car or is it always like this diagram? Logical that if I just mate up the shim against the big spacer and inner and outer bearings that it should mate up cleanly to only one side or the other? Like the shim won't go past the little shoulder on the hub to be on the outside bearing if its intended for the inside bearing?

Or am I overthinking this and I should trust the diagram is correct and this was just bad luck, a bad bearing or maybe I didn't grease it enough?

 

I was able to definitively answer my question about the shim by matching its ID and OD on the big spacer. It goes on the inside, facing the inner bearing, as shown in the diagram.

Got it all back together last night. Rockauto sent me a Timken bearing seal for I don't know what instead of the outer race, so I opted to reuse the outer race I had on my car since that bearing didn't seem to have any issues and the race was very clean under magnification. Got the inner race banged in and reassembled everything. I think the failure is down to either I didn't get the inner seal in well enough, I may not have greased the inner bearing adequately or just random bad luck that my bearing was a bad one. Got it all done and used a combination of bits from a ball joint press kit and a wheel bearing press kit to get everything settled on to the hub nice and firmly, since I didn't have access to these tools the last time I did this job its also entirely possible I didn't get the inner bearing and abs ring onto the hub quite as far as they need to be, but this time I'm more confident in it. Got about a half tub of grease in there now too.

Drove the car the 50 mile commute to work thus morning, was nice and quiet, just a bit of road noise from the tires now, so all seems well.

Thanks everyone for chiming in.