About three summers ago I replaced both my rear wheel bearings. An elusive road noise only tracked down on the car lift.
So I was a bit surprised to find last summer that the right hand side one had a lot of play in it. Obviously I replaced it.

Had the rear wheel off this morning to track down an "ABS failure : DSC etc " message ; cleaned the sensor contacts which stopped the message .
BUT found that this same wheel bearing had failed again ! You can joggle the wheel and see the half-shaft movng ! but No road noise.

Has anybody any ideas what could be causing this ?
The car might have done 2000 Km since last summer , its not used a lot.

2.5 V6 ( 2002 ) : not that that matters ?

 

They're known not to keep failing. (Unless you replace with a poor brand maybe.)

 

Also, the torque for the screw nut is something like 300 Nm. So if it is not tightened properly, it will loosen up and deteriorate the bearing.

 

Thanks,
It seems there are 4 possibilities
A the bearings are rubbish: they are from Barratts , they have supplied me with non-specification hand brake pads for my XJS , but for wheel bearings I don't beleive it.
B the guy who presses them into the knuckle is incompetent : that is very unlikely.
C there is an unknown factor no one knows about : statistically improbable.
which leaves
D I'm screwing up !

The only thing I can see to screw up is the torque needed.
Putting all my weight on my rachet gives 350 Mn ( 90Kgs x 40 cm ). I will find a friend who weighs in at 75Kgs !
I can not remember what I did , but I ceratainly have not got a torque wrench for my 3/4" sockets.

 

As I recall, others do not press them in so perhaps that is the problem.

 

With all the problems and replacements I would change the hub next time instead of just the bearing. More expensive for sure but you have replaced the bearings multiple times so something is wrong.
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+1 on replacing the hub. I would also suggest you replace the carrier, which is item number 1 in the image below.

 

Item #2 is the actual bearing? I've been wondering how it is being pressed in place.

For any kind of bearing being pressed into a bore, it is VITALLY important to only apply force to the outer race. You need to use some sort of spacer that loosely fits over the end of the outer race, leaving zero pressure on the inner race. If the inner race is not free to spin while the entire bearing is being pressed into place, you're doing it wrong.

If force is applied to the inner race during installation, that same force is transferred across the precision guts inside the bearing. This can cause flat spotting on the internal *****/rollers and their mating surfaces, and a resultant short life. I do not care to discuss how I know this, but in my defense I was young and stupid at the time. I'm older now...

 

Got a new bearing ( genuine Jaguar part) and gave it to my man with a press ( along with the knuckle and a bottle of wine ).
He said that despite having a lot of play , there was no signs of wear on the bearing he removed !
This can only mean that the bearing was distorted by the forces put upon it when driving as it was not torqued up correctly .
This sounds incredible until you start calculating the forces on this little piece of metal when cornering ! 300Nm is nothing !
I borrowed a torque wrench this time and followed the manual religiously , so if it fails again it will be a mystery.

I was thinking about replacing bearings and it came to me that this is not the first time I have had this problem.
I replaced both the rear bearings on my puddle-jumper a some years ago , and a year after , a mechanic who was looking at a problem
with the robotic gearbox phoned and said a rear bearing should be replaced.
I had just put it down to luck and forgot about it. After all it couldn't be my fault could it ?
And you have guessed correctly - it was the right rear bearing again! The left rear ones I do correctly !
This can't be a coincidence but I can't explain it either !

 

Or when pressed in.

Or ,..

The clue is that others do not have this and do not use just the bearing / a press.

 

Just to add that after crossing the channel and adding a few thousand KMs to the clock , the bearing is still good.
So no mystery - just a matter of using the correct torque when putting it all together again.