KenRudd

Background:
1988 S4 AT, stock rims, less than 1000 miles on a remanufactured rack and new tie rods.

Trying to diagnose a low "clunk" from my left/drivers side front end.
Its subtle enough that with the stereo up at all or the window down, you really only feel it as a very mild "clunk" thorugh the steering wheel. I almost would not have noticed it, but I also just replaced the old tires which were very noisy with much quieter rubber. It may have been going on for a while, but with the worn out old rubber, it just did not show up...

Only happens when I make a right turn and almost definitely comes from the left/drivers front suspension.

Does not happen if I just turn the steering wheel to the right while sitting still, but if I am moving at all, I get the clunk as I make the turn.

Does not happen when turning left.

No other steering symptoms, everything tracks properly, no vibrations, shimmy, noises, etc.

Had a good alignment done by the local 928 mechanic right after the rack and tie rod replacement.

Should I be suspicious of the new rack/rods, or should I look elsewhere? Bearings, bushings, flux capacitor?

I don't mind checking everything, but I would like to start with the most likely candidates!

Also pointers for best way to test each component would be appreciated, or addtional tests I can run to narrow the culprit down.

Thanks!

atb

Make sure that the two concentrics nuts on the lower A-arm are torqued to spec. If they have backed off at all you can get a clunk. This isn't something to do just a visual on or grab the nut by hand, you need to get a torque wrench on it.

AO

Jack up the wheels one at a time. WHen one of the wheels is off the ground, grab it at 3 and 9 o'clock and wiggel it. See if the clunck is present ot not. If it is, then is is most likely steering related, and the aide of a helper you should be able to see play in the tirerod or the outer ball joint.

If there is no play, try grabbing at 12 and 6 o'clock. Wiggle it. If there is play, it could either be somehting int he control arms or the wheel bearing.

Mrmerlin

check the ball joints and the 4 big bolts on the lower control arms, Whats the condition of the motor mounts? see if the pans hitting the crossmember

dr bob

Stupid Stuff -- Make sure the lug nuts are tightened correctly. Verify that nut holding the tie rod end is tightened correctly. Make sure the cotter key is in the tie rod stud. Make sure the adjusting locknut on the tie rod is tight against the outer end. Make sure the inner tie rod is tightened correctly into the rack. Make sure the rack mounting bolts are tight so the rack is secured in the sandwich between the crossmember and the bottom shield. Make sure your mechanic installed new rack mounting bushings as part of your rack replacement.

Plus what the other guys said.

RED SHARK 1990

As mention i have the same clunking sound on the drivers side.Anyhow what is the spec on these concentric circle nut?Thanks

drnick

i had an annoying clunk that was traced back to the motor mount not being tight following replacement!

jon928se

What every one else said plus it may be worth checking the rear suspension eccentrics as well - I chased a random mild clunk for about 2 months that was not really identifiable as to where it came from until it started to get a bit more vocal. But my then I knew it had to be the rear eccentrics as I'ld checked everything else including removing the CD changer and all the toolkit etc.

SeanR

Mine started to do this last week also and we lifted it off the ground last night. I've got a bit of play when I move it at the 12/6 position.

Tonights job is to find out why this is happening also.

Glad this thread popped up.

KenRudd

All,

Thanks for the many rapid replies!

I have my torque wrench, jacks and jackstands ready for this weekend.

Interesting comments about the motor mounts. I will check those ( although I'm not excited about that, PITA!) They were just replaced at same time as the rack by new solids from Carl. It's possible that a nut is not tight there.

Adam- Ditto Red shark 1990, any idea on the torque specs for the concentric nuts?

Dr. Bob- I did the rack myself, so if something is loose, I know who to blame! Easy to check though. I'm sure the rack bushings are new.

SeanR- Let me know what you find, and of course I'll post any findings as well.

AO

88ft/lbs or 120Nm

killav

I had this one direction "clunk" on my first 928 (1984 model) and it turned out to be a loose front wheel bearing.

KenRudd

Killav-

1. I like the color of your S4 and the rims!
2. What is involved in checking front bearing loosness and making the front bearing "tighter"? It may be obvious once I go in there, but I like to be prepared beforehand.

-Ken Rudd

KenRudd

Killav-

Thorugh the miracle of a well defined search I just found this on tightening front bearings:
https://rennlist.com/forums/showthre...Wheel+Bearings

Dennis Wilson

Worn bushings on the sway bars and linkage can also cause a clunking sound. The rear links are also prone to break at the welds if a large chughole is encountered. BTDT

Dennis