Have an 02 xjr...Kind of a strange thing with my front shocks I think.. I had a balance and rotate yesterday, and now my front end bounces like it has bad shocks. Haven't experienced this until now and its been on a lift three times since I've owned it. It was fine before, but does need new upper bushings... does extending the shocks while on the lift have any history of this effect with anyone else?

 

never heard of it, when you push down does it settle or bounce? is there any fluid coming out of them? Wipe them clean and monitor them. Is the car a CATS equipped R? I've heard on here that Bilstein rebuild them in the USA, it may be a cheaper option than new.

 

Yes it has two to three short bounces when pushed, it is an R with CATS.. the shocks are very clean and dry. Just seems odd to come on so sudden, as it was fine before being lifted. I guess its time to replace. Thanks for the tip on having them rebuilt, Ill surely look into it before I purchase new at nearly $400.00 each... OUCH!!!

 

Make sure their electrical connector is connected, seated and clean. Any chance the tire installer knocked one or both connections loose?

.

 

If the car bounces the shocks are bad, and it doesn't matter whether they're plugged in or not. Unplugged they behave as in N mode, like standard shocks.

A while back a XKR owner inquired as to having them rebuilt and either the service was not available or the cost approached that of new shocks, I don't recall which one.

You could replace them with XJ8 shocks and disconnect the module in the trunk to avoid the error display. I have driven a XKR several times and was not all that impressed with the difference between N and S mode.

 

seems like people aren't picking up on the "yesterday".

either there is a tire that was balanced badly, or
wheel badly mounted to hub, or
out of round assembly moved to a more sensitve position

 

I drove it all day yesterday after the rotate just running around... and again today for several hours. It seemed to slowly be coming back to nearly "normal".
Took it into Mercedes of Ann Arbor for trans filter and fluid. And its right back to rock hard and bouncy after being on the lift. The service guy that drove it immediately asked me if I had a lowering kit on the front end or if my shocks were gone... "felt like its sitting on the bump stops" he says.. drove it for 45min or so and seemed to be slightly better again... strange... I'm looking on line now for prices on new shocks.. now that see at home, it visibly is sitting low in the front and seems to just bounce on the springs..


Just an afterthought... is it common for the springs to become weak? It has 112k on it....

 

Try the running about trick and see if they come back, sounds like they don't like being on a lift. Curious but don't shell out until you've got more miles in....

 

Agreed!! Sean, that exact thought prompted my initial post. I thought I had ran across something to that effect at some point during my MANY hours of lurking here on the site... I have had the sense that the shocks were getting weak I'll admit, but the suddenness and the extreme change just seems very odd.

 

I think Plums has it right. Can you tell (have somebody follow you) which wheel is the most offensive -- sounds like you might have lost a wheel weight . . . .

 

Yes the springs sag with age. But low in front probably means the upper shock mounts are gone, also. Search upper shock mounts on the forum for lots of info.

 

Thanks to all for the input guys!


Took a good look at it while sitting flat in the drive...drove it some more... its definitely lost its normal ride height for sure. The top of the wheel wells are now midway down the side of the tire. I appreciate the thoughts on wheel balance or wheel being off kilter somehow, but its not that kind of bounce.. it is fairly smooth on nice black top as far as the tires or wheels... It just pounds hard on the slightest road seam and bounces (suspension bounce) a couple of times. Shocks in my mind. She'll be sitting out for trip planned this weekend. My consolation prize I guess is the trans filter and new fluid are now off my "to do list"... yes on bushings.

 

" You could replace them with XJ8 shocks and disconnect the module in the trunk to avoid the error display. I have driven a XKR several times and was not all that impressed with the difference between N and S mode."

Surely you'd replace them with non-cats XJR shocks.

The sport mode switch has no effect on the suspension settings.

 

See what happens when I try to relate the XKR and XJR? I didn't realize there were non-cats XJR shocks.

But I'm surprised that sport mode doesn't stiffen the shocks in the XJR like it does in the XKR. I would expect that a softer ride in N mode would be important for the sedan.

 

With that kind of loss of height I'm wondering if a prior owner installed lowering springs.

I obviously don't know the sedan suspension that well. Is there a foam spring isolater on the front that also may have degraded?

 

My understanding is that the sport mode doesn't alter the suspension settings in the contemporaneous XKR, either. In both cars the CATS system is autonomous.

 

There's no way that faulty shocks can change the ride height that much. Although they have gas pressure inside, which causes them to entend to their full length when removed from the car, effect on the ride height is minimal. For the same reason, the upper shock mounts can't cause this either.

Broken springs? Collapsed subframe mounting bushings?

Here's an idea - a siezed balljoint. Try jacking the car up a few inches, and see if it stays at the new height.