I have a 1998 XK8 conv

the tires are wearing unevenly, wearing on inside of tire. My mechanic said it needs to modify front suspension to correct camber, and install rear camber shims. then alignment.

Can someone tell me why the car needs modification and shims? I trust the mechanic, just want to understand whats happening that causing the problem.

Thanks

 

Depending on the conditions but I found excessive tire pressure will do the same thing.

Gus
www.jagrepair.com

 

If the front end has never been rebuilt, you most likely need new upper shock mounts.
Camber is set by the ride height with no adjustment. New Upper shock mounts and either new shocks or new lower shock bushing will raise the car about 3/4" and get the camber back into spec.


To check your shock mounts, pop the caps off the shock towers (in between the 3 bolts) and look for crumbling orange foam/the shock nut not being in the center of the hole.


Shock mounts are about $160/pair from Welsh off E-bay, new shocks/Boots/bump stops are about $240/pr. That should fix the majority of your issues.

 

I don't think your mechanic would appreciate being called "it" whether you trust him or not...
But if your ride height is below specs, he's right in that the camber angle is probably the cause of your uneven tire wear, and it should be corrected.
Regards,

 

The upper shock mounts, upper control arm bushings, and sometimes the lower shock bushings eventually break down and crumble away, allowing the suspension to drop by as much as 1.5 inches. This changes the geometry of the suspension and usually causes excessive inner treadwear on the tires. New upper shock mounts, upper control arm bushings, and shocks generally restores the geometry of the suspension to where it should be and the excessive inner treadwear on the tires will stop. As long as your original shim washers are not bent up and worn out, you can re-use them. Just be sure to keep them in the same order on the long bolt as they were originally....

Lots of threads here pertaining to how to do this, OEM shock mounts vs. polyurethane shock mounts, where to buy the kits, etc. Just search using "replacing XK8 shocks and shock mounts" as your search phrase and you'll have plenty of reading to do....

 

+1 on what everyone has said so far.

Mine were wearing bad in the inside. New top shock mounts and coil springs (over 110k miles) fixed it for me. Wear is now normal and even.

Before the fix, it was low enough you could see the negative camber just by looking from the side of the car.

 

a Note on the Rear shims, yes you could change these to restore camber (maybe, stock is usually 4mm and the thickest you can get is 7.5mm) But since the car was in spec with these at some point it's now something else.

 

Have you put a tape measure on it? Rebuilt my 97 everything worn at 120K being all factory. I got about 1 1/2 inch back with all bushings and shock top and bottom, I even did the ball joints but not fun if your boots on them are good you should be OK. Most remedy will be Shock related, however top bushing also allow for some lean in and would strongly suggest replacement while you have them out unless fairly new.

You should be something close to 15 1/2 inch center arch to middle of wheel. As everything wears you loose height and tire leans in.

If it hasn't been rebuilt it needs to before you try to get alignment as these are really intended to be static other than toe as I understand it.

 

I agree here. This wont be a 200 buck fix. Mine 03 was everything written in this post. After all new shocks, springs, upper and low mounts, new upper control arm bushings my 1.5 inch drop was gone. I still have a little camber but have learned here I need the eccentric bolt kit to fit it. Mine is not out far so not worrying about it.
I have read here again about the check bolt needing to be CENTERED. My shop says no, I have had conflicting thoughts on that here. I am told it has no affect on camber?

 

I just had a 4 wheel alignment done on my 98 XK Coupe after replacing a left front hub and bearing. I also put on new wheels and tires, the previous tires, Dunlops had worn badly on the inner tread...they only had about 30k on them.
My mechanic, who I trust, was of the educated opinion that most of the tire wear you'll get on cars like Jaguar, BMW, Porsche, etc. tend always to be on the inner portion of the tire. Irrespective of the spec alignment, over time and mileage the inner portion of the XK8 tire will tend to wear out first.

 

Welsh has upper shock mount as complete poly unit, no kit work needed. Easy swap as oem