XJ6 S1 rear hub "excessive" endfloat

Hi there,

I didn’t pass the MOT test due to “excessive play in rear hub RHS”. So, I jacked up the car and compared both sides by wiggling at the rear wheels. And, yes, there is more play at the RHS when I grasp the top and bottom of the wheel and apply force. But not really excessive…well.

Following the repair manual I’ve extracted the RHS hub carrier. Now I am a bit uncertain what I found there:

Which of these rings is the spacer, that needs to be adjusted?

The bigger ring has 2 red marks, the smaller has no visible mark.

Thanks for your help!

Dan

Small one on right is the spacer. If float correctly set initially, any excessive play will be bearing wear. Hub float of.004" does feel excessive when rocking the tire at 12 and 6, although it is “in spec”. I used zero float on mine last time, wheel doesn’t wobble at all at 12 and 6. The fulcrum shaft bearings also wear. And the U-joints. Take it apart and see
Doug

The end-float is adjusted with the small ring (Item #7) https://www.sngbarratt.com/English/#/UK/FindParts/Families/XJ%20Series%201-3/5/XJ12%20S3/28/STEERING%20AND%20SUSPENSION/14714/assembly/11480)
The big ring is the inner seal track.

Mind you that the play it’s not necessarily the hub bearings, it also could come from the output shaft bearings or even the U-joints.

I think you find these helpful:

Hi Dan…the best description for setting the bearing end float is in the service manual…as already mentioned the smaller ring is the setting shim…if it is just too much end float in the bearings then note that a thinner shim reduces the endfloat by allowing the inner bearing to press in more…too thin and you start to pre load the bearing…you possibly jumped the gun by stripping it down…you would have been better measureing how much end float there was…modern cars dont have the end float our cars are specked to have so most mot guys if they feel movement will fail it unless you show them the design is to have movement…Steve

As Aristides imply, Dan - the shim is to adjust the ‘in/out’ movement of the bearings - not the wheel ‘wobble’…

The ‘top’bottom’ grip wobble may easily come from wear in the inner or outer pivot bolt bearings. Do check…?

Frank
xj6 85 Sov Europe (UK/NZ)
**

Hi guys,

thank you the input sofar!

I have measured the endfloat according to Page K.6 in the manual. There is virtually no endfloat, i.e.
0.03mm = 0,001in. The nominal endfloat should be: 0.1mm = 0.004in.

So, the wheel bearing is rather too tight,

The universal joints look ok…

Probably I measure the end float of the RHS differential output shaft. I cannot find any data in the manual with regards to preloading/play.

I have no idea how to proceed :frowning:

Greetings
Dan

Ahh, I overlooked that.

There is play at the outer pinion shaft! The rear end of the shaft has 0.05mm = 0.002in play, whereas the front end halve has no play in the bearing.

I can see grooves in the rear end:

If I install the shaft turned around, i.e. rear end becomes front end, the play is gone.

Might that be the reason for my “excessive” endfloat??

thanks
Dan

At lest for now I wouldn’t worry too much about the lesser end-float on the hub.
If you read the thread I linked before you will see some of the debate about end-float versus preloading those bearings.
I actually went for preload.

They are set with preload. Impossible to measure with the diff in situ.
If they have play they need to be changed (this was the problem in my case)

They are also supposed to be mounted with preload.
It looks like the inner race was rotating on the shaft.
What is the state of the bearings?
Some Locktite assembly compound between the shaft and the inner race could help, but If it’s too worn the shaft will need replacement.
Hope you noted the position of the shims.
There should be no play whatsoever in this assembly.

Check if the wishbones have any play as well.

**
The original problem was failed MoT due to ‘excessive play in rear hub’, Dan…

It’s sort of cryptic; ‘excessive motion of hub-carrier’ would be more appropriate? Actually; the later endfloat spec is 0,001" to 0,003" so you may be tight - but within specs…:slight_smile:

…so MoT failed for some other reason, and some elaboration from the guys would be pertinent - to know precisely what to do…?

The grooves in the pivot shaft may indicate a problem with the bearings ‘rubbing’ - on the other hand whether replacing or turning the shaft will satisfy the MoT guys…?

Frank
xj6 85 Sov Europe (UK/NZ)
**

I had to get under my XJR and explain to the WoF (MoT) testers where the ‘excessive play’ was coming from, in my case it was the diff output bearings which was within tolerance.

Hello Aristides,

thank you for your reply!

It looks like the inner race was rotating on the shaft.
What is the state of the bearings?
Some Locktite assembly compound between the shaft and the inner race could help, but If it’s too worn the shaft will need replacement.

I’ve ordered a repair kit + new shaft. The bearings looked ok to me but I will replace them, too.

They are set with preload. Impossible to measure with the diff in situ.
If they have play they need to be changed (this was the problem in my case)
This would be annoying… :frowning:

I will try to measure the endfloat at the break disks…I found in the manual:
“output shaft end float: 0.001in to 0.003in”

Is this I should look for?

**
For measuring play in the output shafts from the diff, Dan - yes…

Be aware that the bearings in the output shafts is different from the the ones in the hub carrier. At the hub carrier you measure the movement of the hub carrier in relation to the hub…

Frank
xj6 85 Sov Europe (UK/NZ)
**

Hi Frank,

I would try to fit my measure gauge between the differential casing and the break disks and measure the play there.

Greetings
Dan

More importantly, Niels; did you check the hub carrier play properly? Ie, you apply force to the hub carrier while ensuring the hub is immoved…

Frank
xj6 85 Sov Europe (UK/NZ)
**

More importantly, Niels; did you check the hub carrier play properly? Ie, you apply force to the hub carrier while ensuring the hub is immoved…

I don’t get it, Do you refer to this procedure?

Yep, I’ve had to do that with hub bearings also. Took a copy of the manual when I went back for the retest. Was nothing wrong with it :frowning:

Indeed, Dan - this is the procedure with the hub out of the car. One in-car test is to pry out the hub and measure the play to the hub carrier, which adds the play in the diff output axle bearing play - so the play spec is then 0,005"…

Frank
xj6 85 Sov Europe (UK/NZ)
**

Hi there,

I’ve been able to measure the end float of the output shaft between the differential case and the brake disks:
0.15 mm = 0,006 in

Which is twice the tolerance of 0.003 in.

I doubt that this is the reason for the 12/6 oClock play at my wheels.

I’ll proceed to repair the outer fullcrum shaft and then I’ll measure again the total endfloat at the hub.

Cheers
Dan

Dan,
I would imagine that the SI would have the early type output shaft roller bearings and not the later type tapered bearings/crush sleeve configuration.
The later tapered style definitely called for preload, i.e. zero play.
I can’t help you with the specs of the early type as I am not familiar with them.

Sorry to be the bearer of bad news, but yes it would…
Keep in mind that a play of 0.15 mm at the center would translate to probably three times that at the edge of the wheel.

As I wrote before, I had excessive 12/6 oClock play at the hubs and it was the output shaft bearings fault.

Yes, with one major fault repaired it will give you a better idea.

Hi there, just a quick update:

I’ve repaired the outer fulcrum bearing and shaft. I found the book quite cryptic regarding the procedure to measure the preload. Thanks to a couple of youtube videos I finally got the idea! Big shout out to the producers!!

Well the endplay is still there. And it comes from the inner universal joint of the halfshaft.

The joint looks good, it doesn’t produce any knocking sounds when switching directions.
I believe I’ve replaced it 20.000 km ago (i.e. 10 years probably).

And it is the type without grease nipple.

Anyways, the MOT-guy was ok with it.

And I nearly passed the MOT, still complaints about oil droplets at the pan :frowning:

Thank you all!
Dan