I just joined but have searched this forum on other occasions. I took a chance and replaced the upper bushings myself ( one of the old ones was gone). How does placement of the 4 shims change the alignment. I want to get it close so I can drive to a shop.
Thanks mel98xk8

 

The shims essentially are the alignment. If you have taken them out and do not remember the order and side they went on, not sure I can help.

On mine, the left and right wheels were opposite. Three in the front (right side as you face the wheel) and two in the back (left side as you face the wheel) on the passenger side, the opposite for the drivers side. The shim thickness matters as well. Some are thick, some are thin.

Not sure if that is any help, but you really only have to get it close if you take it somewhere not too far. Hopefully someone more knowledgeable than I will wade in soon.

 

In doing mine, I was able to remember the location - 3 at the rear, 1 at the front. But, probably because I'm supremely ignorant, it is hard to understand how shims between the upper control arm/wishbone wings has much effect on alignment. Tie rod ends, yeah, I get that, but other than a tiny shifting of the wheel centerline I don't grasp the alignment issue with those shims.

Can anyone shine a ray of enlightenment?

 

Thanks for your replies, I was having a hard time understanding how the shims affect alignment and I see that I am not alone. It would appear that if the shims are toward the front then the toe of the wheel would be shifted toward the outside of the car. Am I correct or did I get it reversed?
Mel 98 xk8 white rag top

 

I believe that those shims would be for the camber adjustment... and if you just need to drive it in for an alignment it won't matter if there are shims or not or where they are. I wouldn't drive super far without the shims, but to just get up to the mechanic you will be fine.

The tie-rods are for the toe adjustment...

 

Only a question, but is it not caster/castor that is affected by the shims? Camber would involve moving the top of the wheel in/out which those shims don't seem to affect. Wiki says . . .

Caster
Caster is a bit harder to conceptualize, but it’s defined as the angle created by the steerings pivot point from the front to back of the vehicle. Caster is positive if the line is angled forward, and negative if backward.

Typically, positive caster will make the vehicle more stable at high speeds, and will increase tire lean when cornering. This can also increase steering effort as well.

Most road vehicles have what is called cross-caster. Cross castered vehicles have slightly different caster and camber, which cause it to drift slightly to the right while rolling. This is a safety feature so that un-manned vehicles or drivers who lose steering control will drift toward the side of the road instead of into oncoming traffic.

 

You are correct... I should have said caster (which I liken to the top ball joint being ahead or behind the lower ball joint) while camber is the upper ball joint being in or out related to the lower ball joint). Thanks!

 

The standard set up for NA is;


Left side front - 2 thick and 1 thin
Left side rear - 1 thin


Right side front - 1 thin
Right side rear - 2 thick and 1 thin

 

And that is the arrangement found on our XK8.

 

Thank you everyone for the info
Mel 98 xk8 white rag top