I replaced the front and rear sway bar bushings today and as I was getting started I noticed that that jack just barely would go under the front cross member. The car has stock springs and last time I jacked it up there was plenty of clearance so I was a bit perplexed.

Looking a little closer the front camber looks to be more that it should and having had an alignment done a few months ago, this was also surprising but would explain the tire noise I've started to hear recently.

There were about 2 fingers of clearance between the tire and the fender in the front to start with. I jacked the car up a little an took the weight off then let it down again. It sat higher now, about 4 fingers of clearance and more like normal. Over the next 10 minutes or so it slowly sank to the 2 finger height.

There is a low speed clunk in the front when going over speed bumps and the like. I thought this was the sway bar bushing but after replacing them with PowerFlex the noise is still there.

What could it be that's going on? If the springs were tired I would expect them to settle immediately to their lower height and the car also seems a little young for a spring to wear out. Shocks resist movement but don't usually provide a large amount of up force so I don't see how it could be a bad shock.

The right and left side are basically the same height and both settle to the same place but there is a very slight pull to the right at speed which might suggest an asymmetry.

Car is an '03 and just crossing 70k miles. The upper bushings are originals but in decent shape. The lowers have been replaced with poly a few months ago (that's when the alignment was done).

I attached a couple of pictures of the front and rear to illustrate the height difference.

Any ideas?

 

If your upper mounts haven't been replaced, 70k is about right for their degredation and inability to hold up the shock.

Also, my car did the same as yours before I replaced the shocks with new Bilstein heavy duty replacements ($100 ea). I would put the car down off the jack and it sat higher than when i initially raised it. Later on, it had settled lower. The new shocks kept the right height back near original factory spec, and also, as a side effect of that, improves positive camber so the tires will appreciate the assist.

If I were you, I'd do both the upper mounts and shocks in one go...you'll be happy you did afterward.

for your reference...

 

So the upper shock mounts get spongey in their old age and rebound when you unload them for a while?

I've got the CATS suspension, so this could turn into a rather expensive little fix. Looks like I should start checking prices.

I'd suppose it would also make sense to do the upper control arm bushings while it is all disassembled.

 

If you've got the CATs, I'd just start with the upper mounts first...I know that the labor to get them swapped has already been done, but the active damping shocks are pricey at just under $500 each. The mounts will get you a little height back. Return to the shocks in another 20-30k if they start feeling 'sloppy', or you notice one side leaning more than the other.

 

When you lift the car the tires pull in as they drop. When you lower the car the tires will 'push out' laterally - this doesn't happen completely, immediately. The tires will slowly creep out a certain amount over time as the tread allows. If you were to roll the car forward or backward that would accelerate the drop as they 'roll out'.

Regarding a change to prior ride height, the cushions at the upper shock mounts could be culprit. Also, tire wear will obviously reduce ride height. Springs are like people, the older they are the less they stand up as tall as when they were young. Add it all together and you have your answer(s).

 

Thanks, good advice.

I ordered up a set of Powerflex upper control arm bushings too. Since it will be all apart and need alignment anyway I figure it's a good time.

I've not seen one out of the car and don't have a good sense of the thickness but is it possible to get an inch difference in height when the mounts wear out?

I've seen pictures posted where they were completely disintegrated and coming apart, but from the top at least, mine look ok.

 

You won't gain an inch, maybe a 1/2 inch if a bushing is totally degraded. Most of will spot signs of orange crumbs lying atop the shock mount, and possibly the shock bolt will be offset of the center of the mount if its fatigued.

Did you measure all corners and compare it with the OEM ride height chart posted above? You may be unkowningly very close.

 

Now that I've been looking around a bit I've noticed also that many peeps will replace the shocks but not the rubber strike-out bumpers and dust boots. They won't affect ride height but will keep the tires from eating huge holes in the fender liners. Monroe, KYB, et al sell them, ~ $12-$15/shock. Just something to consider if you're planning on shocks or springs.

 

Ths is what I measure:

14.75" F 14.75"


15.75" R 16.00"

So rear is pretty close to the curb numbers and the front really is down close to an inch. Guess my calibrated eyeball is ok.

It's good advice Beav, and of I do end up replacing the shocks there will be new boots and bumpers too.

I made arrangement to get her up on a lift in a few days so should be able to figure out what to do next. Given the cost of shocks I suspect I'll do the upper mount and control arm bushings then see where it's at.

 

I have the exact problem. The crumbs under the cap and the shock bolt offset. I just bought the upper bushing from a member here in the forums. My front ride height is low and the wheels look to be leaning slightly in to the naked eye....and plus I had tire wear on inside edge. I will measure after my bushing install on Friday.

 

Wanted to thank everyone for their advice and help debugging this problem.

All said and done, she got new upper shock mounts, boot and bump stops, lower ball joints, sway bar end links, powerflex sway bar bushings and powerflex upper control arm bushings.

Wow, what a difference.

Ride height is up about 1/2in from where it was (you were spot on H2O) and back in the tolerance range. That sort of vague floaty feeling in the front is gone and the disconcerting shudder in the steering over uneven pavement is gone.

Alignment is dead on and the steering is now laser precise. Much more communicative than I ever thought a heavy GT car would be.

The last remnant is some noise from cupping on the front tires due to my not noticing the camber change quickly enough but the Continentals aren't directional so I can cross rotate them a time or two and see if that fades with time.

It was a little spendy to do all at once, but I'm very happy with the result and it won't need done again for another 70k miles.

Thanks again to the forum for all the advice on what to check and where to get parts.

 

we appreciate the follow up Charlie, and speaking for both Beav and myself, we were happy to be of help.

 

Charlie,

Good to read details of your resolution and successful conclusion to this issue.

Graham