Rear suspension settings

Just took my 85 XJS to get the wheel,alignment checked. Car has lost its handling so I wanted to get it dialled in. Front has some small adjustments to get in spec but the rear is a puzzle.
Attached the readout from the system for my rear suspension. I have just checked that all the trunnions bolts attaching the lower rear pivot points are intact and they are . It seems to me that there is a variable amount of play in the rear bearings…spin the wheel and sometimes it has top-bottom play but no side to side …then it does appear to have side to side…but no rear bearing noise obvious. I have removed the shock absorber on one side and can’t find any play in the lower suspension arm…or the connection to the bearing carrier…with the wheel off I can’t detect any play in the hub …but it is a lot smaller than a wheel so harder to detect anyway…anyone know what could be going on??? Handling is NOT GOOD…

Here is a picture of the read out…

Top bottom play is often either differential output shaft bearings, or inner fulcrum bearings. My 95 started twitching at speed in a disturbing manner, and I found the inner lower fulcrum bearings were basically gone.

Long shot but check the U/js on the half shafts as well.

I just came back from having another look. I have removed the shock absorbers from the drivers side so the arrangement can be pivoted freely thru all the movement. I can’t get any forward and backward movement of the wheel at the normal ride height which I thought would indicate wear in the lower pivots…how much force does it take to get movement in the bearings??..but pushing and pulling on the top and bottom of the wheel I can feel movement between the UJ cover and the hub carrier…but I can’t get any movement side to side …if I jam a lever behind the disc the top to bottom movement is still there so possibly not the diff bearings. No “slack” obvious on rotation but I dunno if worn UJ’s would also have rotational “slack”…?? If it was the bearings I should get side to side as well…hmmmm…I’m in an “immediately do nothing” frame of mind…something is not right…

Here’s the specs according to my XJS manual

Front suspension
Castor = 3.5 degrees + or - .25 degrees positive
Camber

  • standard .5 degrees + or - .25 degrees negative
  • 3.6 Sportpack 0 degrees + or - .25 degrees negative
    Front wheels alignment 0 to 3.18mm toe in (0 to 1/8in) toe in

Rear Suspension
Camber

  • Standard angle .75 degree + or - .25 degrees negative
  • 3.6 Sportpack 0.25 degrees + or - .25 degrees negative
    rear alignment parallel .08 mm ( parallel + or - 1/32 in)

Bearing hub end-float should be between ,035-,076 mm or .001-.004 inches
end float greater than ,102mm (.004) inches MUST BE rectified
end float is controlled by the spacers next to the universal joint on the drive shaft

Go to OTPubs.com for $86.00 you’ll get the complete manual for the XJ-S plus some other stuff that’s pretty cool. I’ve purchased this for my XJ saloons and the XJ-S and XJ-SC. Very handy I have the hard bound too.

Adjustment - Camber

Adjustment - Caster

I’ve sent you some info. check your Personal message

I think you will find the spacers by the U/j will only affect the camber of the rear wheels. The end float is governed by the spacer between the bearings in the hub carrier.

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Thanks Mark. Good info !
I still don’t understand why I don’t get any side to side movement…but I’m thinking I’ll have to pull stuff off until I find something that is worn…
Regards
Matt

And remember, I describe how to fab that Service Tool JD 25B in the Book.

Thanks Kirby. I’ll also have a look-see thru your “bible” to see if there are any clues in there…