I'm redoing mt upper and lower ball joints on my 1978 XJS.
The driver side upper has four shims all one one side of the ball joint (rear side).
The passenger side has four shims evenly split with two on each side; most links I've read shows the shims evenly split between each side.

Should I re-assemble with the shims evenly split with two on each side for the drivers sides just as the passenger side is setup as?
I do plan on getting a front-end alignment asap upon swapping everything out.

Thoughts?




Thanks,
Steve

 

NO.

I always replace as I found them, fo now.

THEN

Find a wheel aligner who understands, then he can adjust the CASTER, by moving those shims, fore and aft, to get the reading required.

Mine all had a combination of the 4, split as needed to give me what I wanted.

Caster is NOT a tyre wearing adjustment, straight line stability being affected.

 

Grant - thanks for the reply.
I'll put back as they were.

Any Dallas / Ft. Worth folks here w/ recommendations for an alignment shop?
I'll also check w/ John's Cars for a recommendation but figured I'd also check here.

Thanks,
Steve

 

I would just add to make sure your alignment shop does understand how caster is to be adjusted.
It is not uncommon for some to play around with the camber shims in order to do caster by altering the rake of the upper wishbone. This is not a good move.

 

Found this I wrote years ago, explains it all.

 

Hello Grant -

Thank you for the Wheel Alignment info PDF.
Regarding washer shims #14 for Camber - My rig had two very different thickness shims / washers as shown in the pic below; the rear is/was appreciably thicker at about 3/32 and the front at about 1/32.

As mentioned; in the midst of changing out ball joints along with polyurethane bushings (doing top only at this stage as opposed to the lower as not wanting to mess w/ the spring nor removal of the lower fulcrum shaft for simplicity at this stage (right or wrong).

So...
1. Best to put back these shims of differing thickness or find matching thickness by splitting the difference for re-assembly just to get to a drive-able state and take for alignment?
2. Out of curiosity from a novice RE - Why is are the shims closed washers that require removal of the bolts to change? I would imagine for this location you'd expect slotted shims so the bolts do not require full removal for alignment.

Now I'm a bit concerned of sourcing a good shop that can handle the Jag alignment.

Any input is greatly appreciated.

Thanks,
Steve

 

My guess? Somebody not familiar with Jags did the last alignment.

On many cars those shims are use to adjust both camber and caster. This is accomplished by using varied-thickness shims/washers.

Many alignment guys are a bit robotic. They stick with what they know and don't notice or look for anything different. And, in most cases, it works out OK. Sometimes not.

Jags are a little different. Camber and caster adjustments are made individually and at different locations: camber at the control arm-to-subframe attachment and caster at the upper ball joint.



I'd just make it good enough to drive to a decent alignment shop. I've had best luck with those specializing in hot rods, customer cars, etc. They are invariably more inclined to be comfortable with unusual 'stuff' as opposed to franchised chain-type service enters that cater to the masses. But, still, have a chat with them first so ensure they understand where the adjustments are made on a Jag.


So they don't fall out if the bolts loosen a bit ! Clever of Jaguar to think of that but, in reality, it simply isn't a problem. Millions of cars used slotted shims and falling out, while possible, simply isn't a regular occurence.


In the real world this is the norm and perfectly OK; the slotted shims are often used on Jags as few (if any) shops will have the Jag-specific shims.

Cheers
DD

 

Doug has nailed it well.

I would take a trip to a wrecking yard, and gather some slotted shims, they will probably be laying around on the ground.

Reassemble your top shaft WITH about 1/8" shim, front and back. That is the "start point" I have always used.

Reassemble the camber shims as you found it.

Find the suggested guys that Doug mentioned, and get it done. They will be HAPPY to see slotted on the Camber, and will follow suit.

ALL mine had slotted, and never lost one.

 

Just to be clear, it is implicit in Doug and Grant' posts, but I did not see it exactly stayed: the camber shims on the XJS MUST be the same thickness at each end of the shaft. This is so the top and bottom wishbone fulcrums are parallel to each other.

 

I had the opposite. Max caster in passenger side and 2 shims on each side in drivers side. I’m quite sure mine is fine as it is running straight on continental European roads and takes a bit of correction while driving in UK, but as everyone says: you (and I) need to have a shop setting the caster to be sure.
I have just read a test from 1975 from Autocar. The XJ-S is said to have more caster: 3.5˚ compared to the 2.5˚ used on the XJ saloons. Does anyone know how this difference was obtained ? Can the shims give this difference ?

 

Different control arms, it seems.

I don't have 70s info right at hand but part way thru Series III production, circa 1983, the 6 cylinder sedans were changed to the same 3.5º spec. The VIN break for this change coincides with with a change in upper control arms, which is described in a TSB and indicated in the parts catalogs.

It is interesting to note that the V12 Series III sedans carried the 3.5º spec (and control arms) right from the beginning of production.

All that being said, if you had a 2.5º spec car you might be able to reach the 3.5º spec using the shims alone. I'm not sure.

It should be noted that, as far as caster shims are concerned, the idea is to change the location of shims, not add or subtract shims. That's my understanding, at least.

As for all the caster shims being stacked on just one side of the ball joint, well, that always makes me wonder a bit. If staying within spec requires using the maximum available adjustment I suspect something else isn't quite right. It may simply be that using the max adjustment is compensating for wear. Or, perhaps, it may suggest something is bent

Cheers
DD

 

Leo
Moving the top balljoint/wishbone shims from front to back of the balljoint, or vice versa, changes the vertical inclination of the upright (hub carrier) viewed from the side of the car. This therefore alters the castor angle. In the case of the XJS, or indeed any Jaguar with the same setup, moving the shims can achieve this and more.
By contrast, the camber angle (vertical leaning in/out angle of the wheel viewed from the front of the car) is altered by adding or subtracting shims from the top wishbone inner fulcrum shaft, BOTH ends of which must have identical shimming.
If you are setting up the suspension from scratch, first get the camber correct, then the castor, then the toe.

 

EDIT and forgive my oversight...

The 'camber' shims are identical; the thicker washer was from the nut side - only one bolt/nut had a washer and the other thinner shim had fallen where I did not see it initially so I jumped to the 'assumption' that I only inially saw one thin and one thick washer they were both the shims...

I'm going to go ahead and swap in slotted shims to make the alignment tech's job easier.