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Greetings. Still learning about the XJS as I drive it. But boy, what an absolute pleasure to drive. Unbelievable!
Now, to work. My alignment is off and the car tracks to the left (RHD) slightly. Just read Grant's sticky on alignment. Big help.
Two questions:
1. There are two size shims (thick CBC64161) and (thin 64162). Which size does one normally use?
2. Can you help me identify the circled part? It is in front of the wishbone and the upper part seems to be attached to the roll bar? I don't know. The lower part seems crooked and the bushes look like they need replacing. Would members agreed? Could this be contributing to the leftward pull?
The bushes do wear and it does tend to sit normally at what looks like a distortion of the bushes. A worn one does affect handling but I'm not sure if it would cause a pull to one side?
The part number is C46186. Plenty of OEM and aftermarket options available.
I notice "King Brand" springs, the yellow gives it away.
Based on that, someone has had the front end partially apart and not done an alignment when finished.
AS for the shims, I usually put one of each on each top bolt, and I use the Generic Horseshoe style, so the aligners only have to loosen and slide out or in what they need, The OE Jag ones are a washer and the pivot arm must be slid off the studs to get shims in or out, thats why most aligners HATE Jags, and do the quicky tweak.
Down here, any half decent aligner has these Horseshoe shims, they are used on GM, Ford, Toyota, etc etc for a good many years.
Charles
There are three things to align, and you must have the car set up on a laser alignment rig to do it reliably. Find a garage that has one and check that they know how to use it.
Just in case you are not clear about such matters (and apologies if you are), and for clarity when talking to your garage, the three things are:
Toe in or out. This refers to the extent to which the front tyres are not exactly parallel. This being out of spec is by far the most likely cause of your pull. You should get the car set up to 1/2 a degree (about 0.5mm) toe IN; meaning the front of the tyre rim at the level of the axle is pointing inwards by this amount. Note that EACH SIDE MUST be adjusted separately with the rack centred. Some garages are unable to understand this point! Toe is adjusted by turning the track rod ends (the bits sticking out of the rack bellows each end) in the track rod balljoints.
Castor. This refers to the extent that the "hinge" the front wheels pivot on (i.e. the vertical line between the top and bottom wishbone balljoints) is not exactly vertical. Think of a bicycle front wheel; the forks slope back from the hub to the front forks pivot, which is itself at an angle sloping backwards. This is to provide self-centering for the steering. This rearwards slope is POSITIVE castor. The castor is adjusted by means of small shims about 30mm long, that get placed either in front of, or behind, the upper wishbone balljoint. They go between the balljoint and the upper wishbone arm. If all is straight on your front suspension, place TWO of the four behind the balljoint and TWO in front. If MORE castor is required, move ONE from the back to the front - as this will make the backwards sloping angle greater. The factory spec is quite wide being between 3 and 1 degree of positive castor. The castor should be the same, within reason, both sides; but is unlikely to be the cause of any pull.
Camber. This refers to the extent to which the front wheels, looking at them from the front, are exactly vertical. The factory spec is between 1/4 and 3/4 degree of negative camber - negative camber means the top of the tyre is tilting inwards - i.e. when looking at the tyre from the front the tyre is leaning inwards towards the centre of the car. 1/2 a degree of negative camber is what to aim for in my experience. Both sides of the car need to be the same, within 0.15 degree. Camber - from what you posted Grant I think has already explained (bows to the Southern Cross in Honour of the Great XJS Prophet) - can ONLY be adjusted by undoing the top wishbone inner fulcrum pin and inserting or removing shims BEHIND the bit of subframe the fulcrum pin is bolted to. The shims go between the pin and the subframe. MORE shims = more negative camber. Fewer shims = LESS negative camber. The same number of shims must be used on each bolt. I seem to remember that a 2 mm shim alters the camber by about 0.15 degree; but cannot swear to it.
The bottom wishbone under the outer end MUST be totally reliably supported by a solid wood block or similar, with the weight of that corner of the car on it, to make the castor and camber adjustments, as the spring has to be compressed to undo the top wishbone fixings safely. Or disaster and injury will result!
To check the result of camber and castor changes the car HAS to be back on its wheels, so prepare your garage for a bit of trial and error.
Camber shims being adjusted, showing top wishbone pivot bolts being undone This shot shows the castor shims each side of the top wishbone balljoint, and the top wishbone inner pivot in the background. You can reliably measure camber yourself with a straight bit of ally square tube and an electronic angle finder for 10 quid off Amazon or ebay.
Finally, the camber should be set first, then the castor, and lastly the toe. Camber and castor changes affect toe. having written all this, I shall be very surprised if the camber is out. Castor or toe are the most likely, by far, to need adjusting.
Last edited by Greg in France; May 9, 2021 at 02:17 PM.
Part ID Assistance and alignment question
