1999 XK8 Convertible. After advice in the forum that the ride height was affecting the camber and therefore causing some wear on the inside of the passenger front tire I decided to replace the springs. The height from the middle of the wheel to the fender lip of the car was 14.5 driver side and 15.0 passenger side. I only had 63,000 miles on the car but it was 21 years old. After installing new springs, lower ball joints, new Bilsteins and new shock mounts the ride height was raised to 16" driver side and 16.5" passenger side. So, the height was raised but it is still 1/2" higher on the passenger side and somewhat higher than the 15.74" that previous forum threads gave as the spec. I expect the height over the 15.74" to settle with some use but can anyone shed any light on what would maintain the 1/2" difference? (the car has never been in a wreck).

 

Welcome to the forums shayden99,

I've copied your Intro question to XK8/XKR forum for advice from members with the same model.

Graham

 

Thank you Graham, I'm new at this.

 

Just throwing this out there:- could there be a problem with the driver side rear suspension such as collapsing upper spring isolator or a broken coil spring?

If you still have the old front springs, do their lengths match?

I guess you could check if the rear is level by lifting the front wheels off the ground but you'd need to be pretty accurate in getting the mid-point for the jack.

Official ride heights are here. They show a tolerance of ± 0.59" but not sure if that would be valid for cross-axle:
https://www.jaguarforums.com/forum/x...3/#post2146849

 

This might sound funny. But do you think that the driver's side being a bit higher is to compensate for the weight of the driver? Although I've never seen springs labeled as driver's and passenger's side.

 

michaelh, thanks for the response, it took me awhile to dig out the old springs and measure (14.750" vs 14.875"). The old springs look visually equal but I measured standing on a flat surface side by side. To your first point, all was replaced except the upper ball joints when the springs, shocks and mounts were replaced. The rear has maintained the same measurements before and after the front work was done (average 15.875 drivers rear and 15.75 passenger, although it also changes by 1/8" either side after a drive). I've measured the front maybe 6 or 7 times in the last 8 weeks since the front work was done and the front measurements vary by 1/8" after a 30 mile drive (average = 15.875 driver, 16.375 passenger). See thread starter message for the measurements before the work was done. Thanks for the official ride heights link, it looks like I would be in pretty good shape tolerance wise if not for that 1/2" higher passenger front.

 

Rivguy, thanks for the response. It is the passenger side that is 1/2" higher before and after all the front work was done.

 

In addition to the Spring, there are a few other elements that can affect front ride height. At the top there is a bush that can collapse (shown orange material) and at the bottom, there are Spacers. Normally 3 or 4 spacers are fitted at about 2mm thick each.

 

PKWise, thanks for the response & the great pictures. The top "bush" as you call it is referred to as a "shock mount" around here and both sides were replaced when the new springs and shocks were installed. I didn't do the work myself so I'm not sure about the spacers at the bottom of the spring. I will crawl under tomorrow and take a look - I can see this could be a cause of some height difference between the sides but hard to believe it would cause 1/2" - I will report back.

 

Frustrating. The rear is only slightly less than nominal and the difference could be attributed to what's going on up front. We're only talking tenths of inches out of spec and IMO it will have no effect other than fractionally on camber, although my OCD would seek to know why there's a difference across the axle.

Given that the upper shock mounts are new, there's not much else other than spring compression rates and the spacers as suggested by PKWise?

FWIW, Mine has just a single spacer other than the white plastic spring seat.

 

PKWise & michaelh, I have looked at the bottom spring spacers and there are none. Just the spring setting on the shock lower spring collar. Maybe they had disintegrated over the 21 years and the shop just put the new springs back on the lower mount/collar and moved on. I can see this could be used to modify ride height a bit but really doesn't account for the full 1/2" higher on the passenger side. I don't hear any noise from not having the spacer/s - do you think this could be a problem?

 

Something just occurred to me. What if the front anti-Roll bar is twisted? It may influence the car to lean.

One easy way to check is to disconnect one of the drop-links and park on level ground. Then do a re-measure. Just a thought....

 

Thanks PKWise, I'll take it back to the shop and try the bar disconnect there. In the meantime I'm still trying to find out more about the spring packers/spacers since I don't have any of those at the bottom of my springs. I haven't found anything about it yet in the shop manual either.

 

I have removed the wheels and had a close look at the spring bottom mount. There is one white plastic spring seat on each side and no packers/spacers on either side. I don't know if this is relevant but the top shock mount on the drivers side moved off center toward the front after the new shock and spring installs - the shop says there is no adjustment for this and that it is OK as to suspension function.

 

Shayden, when was the last time you replaced the upper shock mounts?

This is always the 1st cause of height too low, I thought you said you replaced with new way up top in this string, but I can't imagine how ann off center shock as described wouldn't indicate failed mount.

John

 

Hello John, thanks for the response. Yes, the beginning of the string was about a 1/2" difference in ride height, the cause of which I am still trying to find. Yes, the shock mounts were replaced in August, about 800 miles ago and the movement of the shock stud to off center took place nearly immediately. The "plates" inside the shock mount seem to not be fixed in place and can shift around - I just don't know why the drivers side shifted off center. The passenger side (the side that is the 1/2" higher) is perfectly centered.

Driver side

Passenger side

 

If the off-centre is small, then the effect is likely to be more aesthetic than functional. The misalignment will be accommodated by the 'spherical joint' characteristics of the lower shock bush. However, I would not be comfortable with the degree of offset in your pic of the driver side. Passenger side looks fine. Are these OEM or aftermaket parts?

Spring/ride height is key to camber setting.

The workshop manual is vague about the packing pieces:- "Springs come in various ratings depending on the vehicle's suspension specification The suspension specification also determines the number of packers fitted between the lower spring pan and the spring."

edit: JEPC shows that the 'road spring kit' includes the packers, so I imagine there's some work done around tolerances at the manufacturing stage.

 

Thanks michaelh, as I understand the packer usage it would only be of use if the ride height was under spec. As it is, both the front sides are over spec. Driver side only slightly and will likely settle as the new spring ages. The passenger side is a full half inch over and I doubt will settle into spec. Anyway neither side needs a packer and they don't have them, so the possibility that the extra half inch was due to too many packers on the passenger side in now a non-runner. I have measured about 10 times over the 800 miles that are on the new parts and the drivers side average is 15.789 and the passenger side average is 16.363.