TexPorsche

I have a 2005 997.1. I bought the car late December. When I bought it there was a thud you would hear when going over sharp bumps, anything with a severe drop or rise in the road.

The tires were 6 years old and hard as rocks. Replaced the tires with Michelin Pilot SS. I have checked the shocks for oil leaks, checked and tightened mounting points, checked coil springs for damage.

I have adjusted the tire pressure from cold 30 psi all the way up to 44psi and the problem still exist, however not as severe at lower psi.

I have checked the motor mounts no issues.

This week I was installing Fister mufflers, had the car up on jacks and was able to move the rear suspension up and down with a jack, no issues.

The only thing I noticed was what is in the pic. This is the lower wishbone? Regardless of the name I noticed that it looks like this point can be adjusted and that it is "clean", meaning is there movement within the connection? Could this be the source of the thud? It does look concentric and I wonder if this is an adjustment point for rear alignment?

Any thoughts? Apologies on the pic, its upside down....

Bruce In Philly

Hmmmmm sure looks like that may be it. That oblong washer is used to make variable alignment settings... You should be able to get in there and tighten it down.... If it is moving, you should know it if you can get a wrench on there.

Regardless, I would go get an alignment and have them check the tightness of the various bolts. Especially since you just purchased new tires. These wide wheels can wear a tire out pretty darn quickly if the alignment isn't spot on.

With the car up on a jack, can you stick a pry bar in there and make it move? I would try this.

Peace
Bruce in Philly

Petza914

That's called the rear eccentric for camber adjustment if your talking to anyone about it. Also check the lower control arm to make sure they're tight and the ball joints aren't damaged.

nwGTS

Check the bushings on your sway bars between the sway and the subframe and also check the links.

TexPorsche

Sounds like might be time to replace control arm bushings, sway bar rubber bits etc....

sullivas

Just found my front end thud and it was the bolt that holds the lower control arm to the mount on the crossmember. The bolt was loose, I could turn it with my fingers. Try jacking up each side and see if you can move the rear wheel side to side. Hold the tire at different positions and see if you get any play. I got the most play at 8 o'clock and 2 o'clock position.

TexPorsche

Replace links and sway bar bushings, noise is gone. Thanks for the advice. Appreciate y'all.

TexPorsche

Replace links and sway bar bushings, noise is gone. Thanks for the advice. Appreciate y'all.