Very cool

Overnight my '99 Box has developed a loud clunking noise when I hit a pot-hole in the road. If I push down inside the rear trunk while parked up I hear a bumping sound. I get this even with each side of the car supported on a jack. I can detect no play in any of the suspension linkages or shocks and the exhaust heat shields are secure. I replaced the two long trailing arms last year along with the front engine mount.

Any ideas please?

Nothing should move in that case.

Normally I would suggest you check the sway bar bushings (make sure they are in place and torqued to the proper spec) but that is part of the suspension.

The Clunk only happens while driving when you hit a rough bit of road. The Bump shows up when parked and pushing down inside the rear trunk.

Whether this has any relevance but one of the short 10" long cables with snap ball couplings, between the folding roof and the inside of it's stowage compartment has snapped.

Could it be the top bouncing off the body? Try replacing the cable and snugging the top and lets see what it sounds like.

I have removed the broken cable parts and been for a test drive. The clunking sound now seems to come from the front passenger side suspension unit........! I have replaced both L & R lower control arms with the ball joint. Could it be the arm which connects to this?

Edited 1 time(s). Last edit at 01/24/2011 11:58AM by Laz. (view changes)

No, I don't have a hard top.

After tapping the front suspension components with a hide mallet I found a horse shoe size portion of broken coil spring!

I have ordered a new pair and hope to fit them with the struts still attached at the bottom.

Yes I will. I have made my own laser set-up.

I'd like to hear details about that.

I have finally fitted new front springs and new shocks. Once I elected to separate the hub carriers from the lower control arms, things got a lot easier! Thanks Pedro for the advice.


My home made laser tracking set-up comprises for each wheel:

3/4" MDF board half the size of the wheel rim, with three adjustable turned plugs. Each board has a small shelf with a cheap laser pointer attached, shining horizontally.

You tie each board back to back with the plugs touching and adjust the plugs so the lasers point parallel over a distance of approx 30 feet.

The boards are then fastened with elastic straps to each wheel. Using a long piece of timber you mark pencil lines where the lasers shine at the front bumper. Repeat at 30 feet away. If the tracking is at 0 degrees they should shine parallel. Using Trig. you can easily work out the total tolerance from toe in to toe out.

Not as super accurate as an expensive four wheel job but my tyres wear even and steering feels spot on. I have checked the rear wheels previously using fine string lines and found they both toe in slightly as per the book.

As a matter of interest I had to give one track rod end one turn to get things re-aligned after replacing the shocks.

I have had clunking from them in the past as they have gotten old - happens when you hit bumps, park the car and then reverse out of the spot, etc. - it is an integrated bushing that tends to wear out every 75,000 to 100,000 miles. Particularly if you drive the car where you get salt from the roads, lots of dust or sand, tends to corrode the bushings and they can lead to the clunking noise you are describing. It would also be consistent with even getting a noise when the car is on jackstands, as you don't need that much play to make the noise (which is why it is hard to diagnose).

This is, based on my discussions with others, one of the most common sources of clunking noises.

Of course, a broken spring will do it too!

1998 986 Turbo-Look Cab
172,000 Miles
Dilithium Crystal Supercharger

Yes. I have changed both over the last few years. And the rear long trailing arms. ANd the front engine mount. And the anti-roll bar bushes. And the drop links!

Removing one of the pins holding the suspension tower into the hub carrier is proving to be a right Royal pain in the a*$...! Hammering (sledge) with a drift has only moved it 3/4". Hope to try heating the carrier and using a long thin slotted wedge on the other end. Failing that it's take it to a garage time!