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I've used speed bumps to narrow down where the thunk is coming from drivers side front.
It can be heard if I go over a speed bump, or when I am applying the brakes at a slow speed.
I installed the VBP front monospring + sway and the rack attack over the winter.
Last night I got under the car and checked all the nuts/bolts, everything is snug.
Any thoughts as to what could be causing the thunk?
Have you checked the condition of the control arm bushings.
I've got the same noise on mine under the same conditions and the upper control arm bushing is shot.
It's on my list of things to do.
Upper control arms are from VBP as well, bushings are poly.
By shims, do you mean one of them could be missing?
I did have an alignment done a few weeks ago.
St. Jude Donor '05-'06-'07-'08-'09-'10-'11-'12-'13-'14-'15
Originally Posted by ...Roger...
Yes but most likely all them fell out. Pretty common for the techs not to tighten them enough.
Same thing happened to mine when my wife and I were out on a cruise about 60 miles from home. All the shims on the driver side fell out of the upper control arm allowing the arm to move in and out on the studs making the thumping noise in my car.
I think everybody else has covered the first places to check, but I had this problem...going over a speed bump at a "normal" speedbump speed and I'd get a clunk. If I eased over it, nothing. My problem was the upper control arm hitting the frame. The car had BB springs, and I have a light SB (ZZ4). My ride height was about 2" too high (avatar picture). I put in a SB front spring, problem solved. My bushings were all new from the first attempt to fix the problem.
Not sure how the new monospring is affecting this, but look for evidence of the UCA hitting the frame.
Upper control arm shims, open the hood and look at the mounting point of the arm to the frame.
I tried two things,
1) took the wheel off and jacked up the suspension, didn't see any movement at all.
2) grabbed the spindle and tried to shake the hell out of it, to see if I could make the A-Arm (or anything for that matter) move.
Everything was tight.
That won't prove anything. Open the hood and examine the area where the alignment shims should be. Confirm that all four sets are still in place with the nut torqued properly.
Nuts are tight, shims are in place except for one, but i'm sure there weren't any when it came back from the alignment shop.
Bushing bolts are tight as well.
A-arms do show marks where they have hit the shock tower (firewall side), but that's a pretty extreme angle I'd think and I'm wondering if that happened when I was installing them.
went for a test drive after, thunk is there when I brake, as if something is shifting.
Nuts are tight, shims are in place except for one, but i'm sure there weren't any when it came back from the alignment shop.
Bushing bolts are tight as well.
A-arms do show marks where they have hit the shock tower (firewall side), but that's a pretty extreme angle I'd think and I'm wondering if that happened when I was installing them.
went for a test drive after, thunk is there when I brake, as if something is shifting.
a-arms are new, from VBP with new poly bushings. I checked the bolts, they are tight
Poly bushings are prone to sliding around, just a suggestion.
I would suggest you open the hood, support it well and make your stops while sitting high in the seat and watching the action of the control arms. Sorta hard for us to guess, when everything we suggest is new and you think its tight and correct.
From: Who says "Nothing is impossible" ? I've been doing nothing for years.
I'm betting alignment shims too, do you have 2 on one bolt and 1 on the other ? Then the 4 one is on the alignment rack, it would hard to simulate a 3000 lb car going over a bump.