New rear springs were fitted recently after one was found to be broken and since then the headlights have been too high. Investigation found the rear of the car is sitting approx 30mm low according to spec. The dealership have checked it over and found nothing wrong except the dampers are weeping a little and they are saying that's why it's low. I can't see that myself, I thought the shock absorbers were to damp suspension movement and the height was controlled by the spring, any advice greatly appreciated.

 

MCW, a basic shock will have a very minimal effect on ride height if any at all. Like you are thinking, a shock absorber is only meant to prevent the suspension from bouncing over and over by offering a certain amount of resistance to movement.

With this being said, there are 2 exceptions to this. When shocks are new and have a full charge on them (especially your higher end, maximum dampening style), there will be a certain amount of "lifting" that the shock will do as the gas charge inside the shock is trying to push the shock shaft out. But, if you have ever replaced shocks on a vehicle, this force is relatively minimal (say 50 pounds worst case). On a car with coil springs where the spring rate is say 100 pounds per 25mm (going low here, the X-type as I recall has a higher spring rate than this), that would worst case only amount to a 12.5mm height change.

The only other type of shock that would affect ride height is what is referred to a coil over shock. In this case, it can have a significant effect on ride height as you are essentially adding a second coil spring to the rear suspension if you were to add it to the X-Type. To the best of my knowledge, there is no coil spring made for the rear end of the X-Type. So, this becomes a mute point. I know it was never added as a feature from the factory.

With the question about ride height, are you sure that they installed the correct coil springs? I say this as there are 2 different coil springs for the X-Type. You have coils for a standard X-Type and then you have the coils for the Sport. The difference between the two coils is that the Sport version has a higher spring rate (ie, will ride a little harsher, but keep the car flatter in corners) and the Sport spring is 1.4" shorter (ie, 35mm shorter) than the standard coil. To me, this seems to be more likely the situation, especially if you got an aftermarket coil as these tend to be the shorter coils since that is why most people would be replacing the coils in the hope of lowering their vehicles.

 

Hi Thermo, thanks for your thoughts. The springs were supplied by the local Jaguar dealership and I fitted them myself. They have rechecked the part numbers and it appears they supplied the correct ones. That's only the record obviously and doesn't rule out the springs being incorrectly labelled. I did notice that the splash of colour on the new ones was different from the old but can't remember what either were now. The dealer is getting some more springs in and I'm going to see what colour splash is on mine, that may show up something. Very interesting the difference in length between sport and comfort springs, is it a coincidence that my car is low by approx the same amount I wonder?

 

MCW, the color splash on the coils does mean a difference in the springs. Looking, you have 4 possibilities:

-Green: rear road springs, comfort low
-Green/Green: rear road springs, comfort high
-Violet: rear road springs, sport low
-Violet/Violet: rear road springs, sport low

So, take a look at the spring and see if you have violet/purple bands on the springs. if so, this would confirm the issue at hand.

If you are curious, I found this information on TSB XT204-01. If you need a copy of it to prove to the dealership what is going on, then let me know (send a PM) or you can possibly find the information on this site.

 

Thanks Thermo, I found the TSB on jagrepair.com

I'll update after I've seen what colour my springs are.

 

They are white.
Dealer has another set and they are white too, they are now taking it up with the factory.

 

MCW, it is almost sounding like they have the wrong springs as their parts list is showing the wrong part for them to order. I wonder if they happen to get a set of say S-TYpe springs instead of the X-Type springs. Or, could they possibly be getting your 2 jags confused and ordering springs for your XK8, not your X-Type?

 

Thermo, no I wish it was that simple, the XK springs are about twice the size of the X-type's.
Jaguar are now speaking with their supplier to see if all is in order there.

 

Ok so the cause of the low ride height has been identified. There is an error in the Jaguar parts catalogue, it gives the part number for a sports suspension spring but it's listed as standard suspension. Car going in for replacements all under the parts warranty which also covers labour.

 

MCW, that is what I had said at the beginning.

 

Yep, indeed it was and thanks for your input. Your suspicions were relayed to the dealership but naturally they had to carry out their own investigations. They parts dep't manager told me that he's never known a part list error occurring before so I guess it was the last thing they checked.