Jaguar XJS - XJ6 - XJ12 Front Axle Wear...

From Kirby Palms
"Experience in a Book: Help for the Jaguar XJ-S Owner"

The inner races of the inner front wheel bearings tend to turn on the axles. As a result, they eventually wear a groove in the axle, on the bottom where the load is
This allows the wheel to wobble even when the bearings are adjusted properly, and your Jag starts driving like a Pontiac.

To check for problems, remove the front hubs and check the stub axles for a wear groove.
Run your fingernail along the bottom of the axle from the upright outward.
If your fingernail catches at all, the axle should be replaced.

According to Richard Griffiths, the inner race is supposed to rotate on the axle.
This distributes the wear evenly around the inner race rather than concentrating it on the bottom. “With proper lubrication, heat treat and tolerances etc., the effect of a "walking" inner race on the axle is a beautiful mirror-like burnished surface, not galling and wear as some have noted.”

Well, there’s little an owner can do about heat treat or tolerances, and on the XJ-S inner race rotation is clearly a problem -- and bearing wear is not a problem.

So it makes sense to ensure that the inner races will not turn by using Loctite 640 or some similar high-strength bearing retaining substance.
This may shorten the life of the bearing by some negligible amount according to some engineer’s theories, but in the real world it will positively eliminate the wear on the stub axle.

Use it on the inner race of the outer bearing, too, since it has been known to have the same problem. Adjust the front wheel bearings as described below.

Section 60.25.13 of the ROM, Step #4, indicates that the front hub bearings should be adjusted to attain end float measurement of 0.002”-0.005” (0,05mm-0,15mm).
However, Technical Service Bulletin 57-15 revised the end float spec to 0.001”-0.003”.

If you don’t happen to have the type of dial indicator needed to measure end float, this author recommends the following procedure: Tighten the retaining nut to perhaps 20 ft-lb while turning the hub to make sure everything is seated properly. Loosen the nut then spin it back on until it seats, normally a very distinct point; continue to tighten about 1/10 of a turn while turning the hub. Fit the lock and install the cotter pin.

This may seem tight, and in fact may be tighter than the official Jaguar procedure (measuring end play) would result in. Any bearing expert will tell you that proper operation of a roller bearing requires some preload. When tight, the weight of the car is distributed among the rollers. When loose, the slop allows the load to be taken by only one or two rollers at a time, and the unloaded rollers may slide rather than roll.

Another method that has been suggested is to tighten the nut to 25 ft-lb while rotating the hub and then back the nut off one flat.

If you’re using Loctite on the inner races as suggested above, you might opt to apply the Loctite to the inboard race, assemble, tighten the nut to 25 ft-lb while rotating the hub and leave it there long enough for the Loctite to set. Then pull the nut and outboard inner race back out, apply Loctite there, and then do your final assembly and adjustment.

Note that having the bearings adjusted too loosely -- as well as having a grooved front axle, as described above -- would be detrimental to seal life. And the seals on the ABS-equipped cars may be marginal already, as mentioned above.

You can find more about the bearings at the STUB AXLE section/post on this site...
That I will write and post later on... so keep coming back...

If you would like a copy of... then Download a PDF version of by Kirby Palm's Experience in a Book: Help for the Jaguar XJ-S Owner HERE

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