[xj40] rear wheel bearings 93 vanden plas

XJ40
1

I have a 1993 Vanden Plas. Can the rear wheel bearings be
adjusted/tighted like the front? If so are there any special tools
needed?

Also what are typical sounds/noises associated with a worn or bad
wheel bearing? (ie thumping, whining, grinding, humming, etc.)

Thanks!

Mark–
mark kosisko
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2

In a message dated 11/15/2004 10:50:08 AM Eastern Standard Time, “mark kosisko” kosiskom@rssc.k12.in.us writes:

I have a 1993 Vanden Plas. �Can the rear wheel bearings be
adjusted/tighted like the front?

Also what are typical sounds/noises associated with a worn or bad
wheel bearing? �(ie thumping, whining, grinding, humming, etc.)

Mark:

The rear wheel bearing end play is not a function of nut torque, but rather of preload build into the system via the dimensions of the hub carrier race shoulders, the bearing dimensions, and two spacers inside the hub. The rear axle shaft nuts are torqued to ~ 230 Ft-lb. and cannot be reused of loosened.

You can check the hub for end play to determine wear, but if end play or noise is excessive, the bearings must be replaced.

On my 89, I was getting a “roaring” noise, similar to the sound made by knobby off-road tires on hard pavement, from the rear (as opposed the the whine one gets on deceleration with a bad pinion bearing), and this noise was not speed- or throttle-dependent.

While I was replacing wheel bearings on both sides, I also replaced the output shaft bearings on the differential, even though there was no excessive end-play there, so I can’t be absolutely certain my noise was wheel bearings rather than output shaft (but I believe it was from a wheel bearing).

When I had a wheel bearing go bad on the front, it made a “groaning” noise, similar to a power steering pump low on fluid, which occurred in a turn at speed in one direction only (e.g. a right hand turn at 60 MPH loading the left front wheel where the bad bearing was).

George Balthrop, Clifton, VA USA
85 & 89 XJ-S Coupes; 89 XJ40 VDP

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3

In reply to a message from mark kosisko sent Mon 15 Nov 2004:

Mark,

The rear wheel bearings cannot be adjusted. They can be replaced
using ordinary hand tools (although the factoery service procedure
and Haynes calls for press tools!). Many people on the list have
done this job - read through the archives.

Typically a worn wheel / hub bearing will emit a low frequency
humming noise which varies in intensity with road speed. However,
on an XJ40, a similar noise, but perhaps ‘grinding’ rather
than ‘humming’ and maybe at a higher pitch, can be heard from worn
differential output bearings and that can vary in tone when
cornering as side loads are put on the bearing because the half
shaft also acts as the upper control arm of the rear suspension.

You should really confirm if you have worn wheel bearings by
jacking the rear wheel and rocking it in the horizontal plane to
detect excessive movement. If you then rock the wheel in the
vertical plane you will get the same degree of movement from worn
wheel bearings plus any undue wear in the diff output bearings.
Have an assistant check for any excessive end play (there should
only be a little) between the diff output shaft flange and the diff
housing to check for wear in that bearing.

Of course, there is also the possibility of wear in the drive shaft
U-joints, particularly if they have not been greased regularly at
the required service intervals.–
The original message included these comments:

I have a 1993 Vanden Plas. Can the rear wheel bearings be
adjusted/tighted like the front? If so are there any special tools
needed?
Also what are typical sounds/noises associated with a worn or bad
wheel bearing? (ie thumping, whining, grinding, humming, etc.)

–
Bryan N ('91 Sovereign 4.0 L)
Cambridge, United Kingdom
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
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4

In reply to a message from GBalthropXJS@aol.com sent Mon 15 Nov 2004:

George,

The sound you describe (like off-road tires) is very close to the
sound I’m hearing (I just couldn’t describe it). Is this a very
big job? (approx. hours)

Thanks,

Mark–
mark kosisko
–Posted using Jag-lovers JagFORUM [forums.jag-lovers.org]–
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