I have 2 aluminum spacers approx 5/16" think and no idea where they go. The bolt spacing matches the castor position at the upper ball joint so I suspect they go there? One each side? Forward or rear position or does it matter? Do these simply substitute for a bunch shims as needed or is there another purpose? Also, is there a base setup for the number of castor/camber shims when doing initial setup? Unfortunately I didn't record the existing setup when I disassembled the beast. Thanks for any info.

 

This is the way I did it. I assume it is correct. Bob

 

There is always a set total thickness of shims, but they can be moved front or back
to set caster.

... sez the guy who's never seen one

 

Thanks Bob and rd - at the end of the day I guess the alignment guy will sort it out.

 

I have to say the set-up doesn't look correct to me - there seems to be far too large a thickness of spacers, but of course the modern sealed ball-joint may not be as wide as the old ones.

As said by Plums, there is a defined distance between the two arms of the upper wishbone, which the ball joint and spacers fill. Shims allow the ball joint to be biased to one side or the other to set the castor angle. AFAIK, there is, somewhere, the castor angle change per shim of a certain thickness.

 

I consider it correct as I reassembled as it had been. That may or may not be correct. Bob

 

Hah!

It's quite common for alignment guys to add/remove shims on this setup.

That is wrong because it upsets changes the shape of the arm as a
whole. That would bind the inner bushes.

This setup is used up to and including the X300 and XJS, so there
should be someone around here that knows.

 

According to the Kriss Motors website (Front Suspn Part 3) a 1/16" shim equates to a change of caster or camber angle of 1/4 of one degree.

Apparently, if using modern radials, the recommended caster is 2-3 deg. +ve and camber angle 1 deg. negative. (have not tried these yet myself).

 

Thanks for the alignment specs.
I compared the width of the newer sealed ball joint with the original style and they're identical. I posed the question regarding total shim thickness to a friend on the left coast who as a young man was a mechanic at British Motors in San Francisco - guessing he followed the proper procedure hundreds of times in the day. Will let you know what he says.

 

The official answer was "about half an inch - the precise measure isn't critical." Sure enough, when I measured the gap on the top end with fresh urethane bushings it was just over half an inch. If I tightened the castle nuts a bit further we'd be spot on. The idea is not to put any side load on the bushings.