Was driving earlier today in nice weather and for once I had my passenger side window open. When I turned the radio off, though I noticed a “foreign noise” coming from the right rear wheel area of Superblue. It was faint, but a continuous high-pitched squeal-like sound that continued as long as the wheels were rolling (more noticeable at higher speed) … I’m thinking wheel bearing (or hub/carrier bearing?). Never heard this one before, although about 3 years or so ago I had a front left wheel bearing (Superblue) actually fail on me, damaging the spindle/hub. It was not a cheap repair, either , even at PepBoys. I can’t recall if this is the same sound the wheel was making right before the failure or not.

Anyway, what are your thoughts on this? Seems like I remember back in my XJ40 days there was a quick test to determine worn bearings. Don’t know if the same test is applicable to the XJS, though, since it has IRS. Something about putting your hands at 12 and 6 o’clock position on the road wheel and seeing if you can wiggle the wheel back and forth, and then shifting to the 3 and 9 o’clock positions to see if it wiggles side to side. If it does just one (can’t remember which of the two), then that = wheel bearing bad. If it does it only in opposite respects (or maybe both?), I think = bad hub bearing. Does that make sense?

I’m going to keep driving to a minimum (obviously) until I can get a tech (NTB) tomorrow afternoon to check it out, and hopefully that won’t make things worse in the interim. I’m thinking if it is a wheel bearing, probably too late to now just re-pack it, but will need to r/r it,.

p.s., a very learned XJS owner has speculated about the possibility of worn out brake pads causing the noise on that wheel, noting that it his experience that a "squealer" sounds whenever the brakes are NOT being applied, to warn of same. If true though then I wonder why my brake warning light is not coming on, since the face-lifts like Superblue have wear sensors located on the rear brakes. (but then maybe it is not functioning correctly ?)

 

Does the noise go if you lightly apply the handbrake?
Does the noise go if you lightly apply the fottbrake?

Wheel bearings failing are usually a hum/whine rather than a squeal.

 

A test I use to identify a failing wheel bearing is to "load" the suspected wheel and see if the noise goes away. In your case with a suspect right rear bearing - if you turn to the left and "load" the right side of the car, does the noise go away?
Now turn to the right and "unload" the right side of the car - does the noise continue?

If you answer yes to both questions you are probably on the right path with the wheel bearing.

 

Haven't tried either, but will do the foot brake thing later today .. thanks!

 

Actually, I did notice this driving hone last night .. Road that slowly turns to the left, the noise was more noticeable .. not as noticeable on straightaway ..

 

I was just looking pu the bearing r/r procedures in the Jaguar factory workshop literature. GEEZ LOUISE! It's no simple job like on any American car. The instructions for the job take up 5 pages of the manual. It requires the removal of a wheel hub assembly (using a special puller), taking it to a bench to disassemble to remove and replace all the bearings, seals, etc. in it, then put back on the car. To finish the job, all kind of "end float" adjustments must be carefully made. Jag-specific tools required, too. I'm just hoping that, Superblue, being a post-face lift model with their redesigned outboard brake assembly, Jag also redesigned this hub/bearing assembly to utilize just standard inner/outer wheel bearings. ?

 

THis is not as difficult as it looks. The real problem will be removing the driveshaft from the hub. Once this is done the rest is pretty easy. A bit of bedtime reading for you here, most of it relevant; but post 35 explains about the spacers:
https://www.jaguarforums.com/forum/x...ebuild-225834/

 

Well, I can see NTB telling me b/c of all that involved labor, they can't help me with this issue. I did look up on the Classic Heritage parts site, and, fortunately, there is a bit of a difference with the hub & carrier between the two models, the face-lift's appearing to be a bit easier to work on than the pre-facelifts. I'm thinking probably the easiest way to solve the problem is not to delve into taking the original hub all apart to r/r the bearings, seals, etc. but just get another good used hub assembly (w. stub axle) and swap them out. There are a few used front ones for sale on Ebay (and at only around $100 or so), but I have not yet located a rear one. I'm just wondering with the swap approach if all that bearing pre-load adjustment stuff is still going to be required, or will it be simple "plug and play" ?

 

Changing the rear hub bearings on the outboard brake version is pretty straight forward. I did it in my workshop with no special tools, just a variety of sockets and drifts to drive bearings in and out.. Obviously, the hub assembly has to be off the car. Bearings are machined to very close tolerances, so the existing shims can be reinstalled as is. ​​​​​​​I believe it is preferable to change the bearings in the hub you have. Any Ebay or other used hub will likely need all bearings replaced, both for the hub and the wishbone attachment. Your hub is a known quantity, and hopefully your wishbone bearings are still good, although they are much simpler to replace than the inboard brake hub type.

 

Thanks, Jal .. appreciate the "good news" .. sure was needed and I now have more confidence in being able to get this taken care of soon ..

 

Well, the noise seems to have gotten more noticeable, and anytime the wheels are in motion, no matter how slow. I would describe the noise as almost a high-pitched "whistling" sound. When I first noticed it, it was a faint whistling sound that at first I thought was maybe the wind blowing through a gap in a door seal or something on that side while the car was going down the road. It still has that sound, but much more noticeable. So, does this sound more like the "brake squealers" (i.e. very low pads on that wheel) vs. a bad wheel/hub bearing? I have been told that, oddly enough, the squealers on the XJS pads tend to make noise when the wheels are in motion and NOT when the brakes are actually applied. If it's the pads, though, I can't figure out why my low pad warning sensor on that wheel isn't tripping the brake warning light. ?? btw, if the pads are low, should it only activate the light when the brakes are applied, or be on 24/7?

 

If it were squealing from the brakes, the noise would stop on application of the foot or handbrake. if the noise is getting worse would seem to me to indicate a bearing getting worse. But pretty easy to check if the pads are worn, whip off a wheel and look.

 

You don't have a low pad warning sensor....you have a low brake fluid sensor.

Jaguars are notoriously frugal with any kinds of trouble light....I would never rely on them to tell me when something is wrong, but I am always grateful on the rare occasions that it does.