Hey all,
So I replaced the rear bearings because both tires would jiggle a bit if I pushed/pulled on the top of the wheel when it was jacked up. So I figured bad bearings.

Well, with new bearings, they still do that. Is this normal, and what parts should I check for wear/damage?

Second question: One of the rear hubs fell right off of the drive axle after loosening the nut. Do I really need to replace that axle? And how much amputation is needed?

Thanks for any insight!

 

It is possible to visualise the rear suspension as a multi-point loop.

starting at the differential, the articulation/wear points are:

- output shaft bearings
+ ujoints
- wheel bearings
+ outer fulcrum bearings
- inner fulcrum bush

to narrow down the possibilities it would be helpful to have a helper
rock the wheel while you feel the movement at the spots being
checked. the most likely *guesses* are marked with "+"

since this requires getting under the vehicle, ensure that it is
raised SECURELY with multiple jack stands and backups

 

The differential output bearings have an acceptable axial play of 0 to 0.15mm. This movement would be exaggerated at the top of the wheel.

 

As others have correctly mentioned you might be feeling free-play from something other than the bearings.

However.....

How did you measure clearances and set your bearings when you replaced them?

The X300s (which I'm familiar with) use shims to pre-load the hub bearings so there is less-than-zero free play. Since X308s use the same rear hubs, I suspect the bearings are supposed to be set up the same way.

I think most people simply replace the bearings and call it good....and get away with it. But, technically, you're supposed to measure-and-shim whenever the bearings are replaced.





I'm not sure that this is necessarily a sign of needing axle replacement.

Did the splines look worn or rounded?

Cheers
DD

 

The fact that the weight of the hub was sufficient to pull the hub off of the axle probably just means the axle wasn't corroded into the hub, which is a good sign. But Doug is spot on to suggest you inspect the splines for any rounding or damage.

One other thing you should be aware of is that Jaguar insists the rear axle nuts be used only one time, so you must replace them with new ones. They have a deforming helical insert to lock them to the axle, and since the nuts are torqued to over 200 ft.-lbs., the helical insert completely deforms and cannot be used a second time. I know of at least two owners whose axle nuts came loose while they were driving down the road because they reused the old nuts.

I've done the rear wheel bearings on both of our XJ40s (the bearings are the same part numbers used on the X300 and X308) and have never had to adjust the bearing spacers. Modern bearings seem to be manufactured to pretty tight tolerances, but as Doug suggests I may have just been lucky.

In case they're helpful at all, check my photo albums at the link in my signature. I have albums on the rear wheel bearings, diff removal (which shows the components of the independent rear suspension), and diff output shaft bearing replacement.

Cheers,

Don

 

Jaguar also says that the splines should receive red loctite. That might make
you feel better.

 

Ok so events have happened!

The right rear bearing failed which i chalked up to not greasing it practically at all, and then I replaced it again which I can now almost do in my sleep; it having been the third time for rear wheels specifically. The bearing failed spectacularly, crumbling into bits after about 200mi.

Now I installed a new bearing, and it's buzzing right off the bat! I didn't get a new spacer and am now worried too about the metal bits having screwed up the hub.

The sound starts at around 20mph and is a low, deep buzzing sounds. It does not go away when turning left or right.

I'm guessing I have to replace the bearing, but now I'm wondering could this all really be due to a worn spacer? I checked the lugs... I also am thinking that I may not have pressed the ABS ring far enough onto the hub, however tightening the axle nut at 250lb/ft should tighten that up right?

 

Installing the new bearings with insufficient grease could definitely cause damage not only to the new bearings but to the hub, spacers, hub carrier, etc., so you'll need to clean and inspect every part carefully.

For the X308, the rear axle nut torque specification is 224-247 lb.ft. (304-336 nM). Have you been torquing the nut to that range? Below are links to photos showing the bearing replacement job on our '93, which is very similar to your car. Note how I apply a "reservoir" of grease inside the hub carrier (in Part 2) and how I pack the bearings with grease (Part 3):


Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page
Welcome to Jag-lovers - Members Photo Viewing Page


The rear wheel bearing replacement procedure begins on page 221 of the X308 Workshop Manual pdf (if you don't have it, send me your email address via private message and I'll send it to you). Jaguar shows the use of a lot of special tools but you don't need most of them.

The hub end-float is measured before the axle is installed and the hub nut tightened and torqued. The float specification is 0.076mm / 0.003 in. (page 231).

Please let us know what you find when you inspect all the components. Something is obviously unhappy.

Cheers,

Don

 

Just to be clear, end float is how far the hub protrudes from the abs ring?

 

End float is how much the hub moves in and out of the hub carrier with the ABS ring fully seated on the inner end of the hub. I've never bothered to measure it, but I imagine one setup would look like this (this photo is of a Triumph overdrive unit but you get the idea):







The alternate method would be similar to checking the float on the front wheel bearings (this photo is of our '93):




Cheers,

Don

 

So I got everything repaired....looks like a bumpy up pressed in 'ring', I forget the term...

New Axle nuts on the way and now I have two extra bearing sets just in case.

I still don't know why the initial replacement failed, however. (I replaced it once, that failed, replaced it again, that was messed up probably due to debris, then just replaced it again and it seems to be working well.

 

I'm assuming with each bearing replacement you are also replacing the race?

 

In my experience, the most common cause of excessive endfloat on the rear wheels is wear in the differential output bearings, not the wheel bearings.