Help Identify My Front End Clunk!

[jmgtp]

Driving me kind of nuts. It seems to only happen on a rabbit start or hard braking. It is a single clunk/pop type of sound and you can feel it just a bit in the floor. If it happens while braking and you let off the brakes and then jam them again it will not do it a second time, that is until you have given it some gas again and then brake again. So its like something is shifting. Going over speedbumps, potholes, etc does not cause the noise. Only HARD braking or aggressive starts.

What I have checked and confirmed it is not:
-Ball Joints (2yrs old - checked for play there is none)
-Tie Rods (2yrs - no play)
-Trans Mount (1 yr)
-Motor Mounts (1yr)
-dogbone mount - (poly bushed - no play)

Things I think it could possibly be:
-springs/mounts
-sway bar / bushings (i have poly bushings that I have since greased)
-bearing plates
-rubber mount in top of strut tower (what is the real name?)
-subframe bushings (they seem ok, tho I have never replaced the torque to yeild bolts and they have been out many times!)

The problem with the 'could be's' is that there is no easy way to really check other than disassembly. I just had a front end alignment done too so I'm not too thrilled on taking it apart and throwing those dollars out the window!

Ideas?

[pocket-rocket]

The way you describe it I wonder if it is your A arm bushings/mounts.

-rubber mount in top of strut tower (what is the real name?)

Are you talking about the strut bearing?

[walterdude]

I'd say check the A Frame bushings also. My 93 Z43 was doing something similar but mine mostly showed up in the steering. I'd get on it and it would pull a little one way until I'd get on the brakes,,, then it would pull a little the other way. Not a whole lot, but I could feel it. Crawl under the car, without jacking, and have someone turn the steering wheel back and forth fairly quick, say 1/4 turn each way. You can use your fingers to feel if there's excessive play in the bushings. If you get it off the ground you can use a pry bar to check for play, tho I like having the weight of the car on the ground. Mine I could actually see it move. Could be sway-bar bushings, you can pretty much see what kind of shape the bushings are in,, with the wheel off. Those and the sub-frame bushings I'd expect to hear clunking/rattling.. Bad subframe bushings can also affect the steering, mine looked fine but, when I got them apart they were SHOT... That was part of my steering issue.
I don't think springs/seats would do that. The strut bearing seldom goes bad. That would show up in the steering. Probably as binding when you steer..

pocket-rocket--- I think he means the rubber bushing/mount at the very top of the strut shaft, on a W Body they pop up when you remove the top plate of the strut tower. If they are loose/worn they clunk/rattle... I can't picture that causing what he describes.
I'd start with the A-Frame bushings.. I'd say that's it... If it's the 91 GTP in your sig it might not hurt to really check out the sub-frame bushings if you haven't already. When I took mine apart there really wasn't much left.. The cars ARE getting old!!!
Well too many words to say not too much,,,,
It's been one HELL of a day, a REAL adventure.... I'm too old for adventures... I don't think I like adventures............
I need to sleep,,,,
sleep,,,
Hope this helps/makes sense...
Tom....

[pocket-rocket]

I thought those rubber mounts under the covers had bearings in them, and they were referred to as strut bearings/mounts. Oh well. I agree, sleep sounds good, lol.

[walterdude]

Those top mounts are mounted solid on the strut shaft and hold the shaft from turning.. The lower portion of the strut turns. The bearing is mounted in the lower spring seat, the spring stays stationary and the whole lower strut housing turns. The two pivot points are the strut bearing and the ball joint.
Here's a few pics I just took for you to SEE....
ThanxXx,
Tom....

[jmgtp]

Thanks for the replies!

I'm going to look into the control arm bushings. When I had my Beretta they went bad and I replaced them with poly bushings (available for W??). Though its been years and I don't remember the symptoms of the bad bushing.

There is no way I can get under the car to check without it being up on stands. It is lowered, but even if it wasn't I doubt I could get under there enough to see. I'll have to raise it up and see if I can get some movement with a prybar.

I don't think it is the swaybar bushings, they are poly and look like new and have been greased.

[TurboGTU]

Engine cradle bolts.

[jmgtp]

Are the cradle bushings/bolts dealer only parts? anyone know part #s? cost for all 4 bolts/bushings?

[jmgtp]

this thread is back from the dead...

The car sat for about a month and I started driving my subaru again daily. I decided for one more week to romp around the in grand prix before putting it to bed for winter. Oddly, clunk is gone. I havent been able to replicate it. Maybe it was the springs somehow, and they have settled after sitting?

I still intend on replace the cradle bushings/bolts, not sure where to get them other than a dealer and I'm sure they'll be pricey. Would gmpartsdirect carry them? I only saw the whole cradle available for a bargain price of $716.01! Does anyone have a p/n I can research? I'd like to replace the control arm bushings while I'm at it. Is there anything poly available? If not what about p/n so I can look them up?

Thanks,
John