Reading a thread on the XJS forum this morning I came across this statement:

I wasn't aware of this and can't say I noticed any eccentric when I removed the rear arms etc?

Also, on another forum, read about problems with the fulcrum shaft bearings disintegrating and the various symptoms associated with that ...

I've got spare rear and front ends and over the winter I plan on rebushing the spare front bits and *considering* replacing the rear fulcrum bearings or maybe the complete arm in the rear.

Even though the VDP really doesn't have any serious rear suspension issues (shocks/springs/subframe bushings replaced 2 yrs ago, one piece dogbone strut installed this year) the parts car arms/hubs have almost half the miles so IMHO a swap could definitely extend the car's life quite a bit.

If I do change the rear arms, I suppose the rear toe will need to be reset?

If so, how?

TIA for any advice

Larry

 

The X300/X308 use a system with an eccentric washer at the rear
of the fulcrum bolt that sits in a slot in the rear face of the lower arm.

Yours may be very similar.

The toe is set by rotating the bolts and then tightening up the nut
to hold the setting. You want just a hair toe-in, and unlike the front,
there is no self centering, so the toe-in must be identical on both
sides relative to the centerline of the car.

DIY is possible, but very fiddly. Turning the bolt is easy.
Measuring the result is the problem.

 

I get it - thanks!

So I'm assuming a wheel alignment shop could set it up for me if I tell them how to do it?

Also, you say the rear isn't "self-centering" like the front ...as all this alignment stuff is all news to me (no experience yet), when you say the front is self-centering does that mean I could use a mix and match number of shims, say 1/4" on the left side and 1/8" on the right and that would result in an even 3/16" on each side?

Larry

 

The 1994 (maybe some 1993?) had a 'stamped-steel' lower control arm that had provisions for 'toe-adjust'.
The earlier cars had NO such provision.

The stamped-steel control arms were discontinued/superseded to the X300/X308 arms with a kit to accomplish this.

The kit was ridiculously priced at about $600 with lower control arms, springs, dampers, bushes, etc.

The labor was about what the parts were. It was a BARGAIN and I installed a few. I thought about getting a kit because I knew it was an appeasement for discontinuing the parts. The kit came in a REALLY nice wood crate and all the original stamped steel parts and related components were required to be returned to Jaguar.

You can replace the 1988-1994 lower arms with salvage yard components to have the adjustments or swap all the rear suspension components with a suitable X300/X308 set of replacement parts.

Here is a PARTS TSB with the info.

bob

 

Thanks Bob - both of my 94's have cast wishbones just like the X300's so I guess I'm good to go?

Larry

 

self centering:

on the front if the toe is different on left and right, then as the car goes
down the road, the toe will equalise with the result of the steering wheel
being crooked. the toe is still equal on both sides because the wheels
are free to twist.

no such effect on the rear, so the toe has to be equal on each side
relative to the center line or you get "thrust angle".

yes, a four wheel alignment should get this right.

 

I think I get it ... I've read about the steering wheel being non-12 o'clock (mine is like that on the VDP) and also read about remediation by adjusting each side of the rack equally to get it to center ..so this symptom could be related to the alignment and not just to the rack being out of whack?

Sorry to be so thick, just trying to get my head around the subject before I dive in!

Larry

 

if your steering wheel is crooked, unequal toe when the steering
wheel is centered is the usual cause. yes, provided total toe is
correct, then it is fixed by turning both equally to centralise
the wheel. turning equally maintains total toe.

on the rear, no freedom of movement for steering, so the toe must
be equal to prevent crabbing down the road.

 

Larry,

For the benefit of other readers who may have earlier cars than yours, our '93 has stamped steel rear control arms with no eccentric bolt like that on the X300/X308, and as far as I know none of the XJ40s had them prior to the changeover to the X300 rear control arms that were cast or forged. I can't recall whether that happened with the introduction of the '94 model or sometime later during the '94 model year.

Cheers,

Don