Over the past year, I have done a lot of suspension work on my '84 300TDT wagon, as well as other work, and now I have a bumping noise from the right front of the car only when going over "washboard" type of surface. Here is what I have done:

Rebuilt SLS valve, new air cells, works great
New sub-frame mounts
New guide rod mounts
New guide rod bushings
New upper control arms
New front torsion bar bushings
New steering damper
New tie rods (note...These were off brand...all four rubber boots are completel broken after 6 weeks)
New rotors, rebuilt calipers
New Wheel bearings
New ball joints
New Bilstein comfort shocks
New rubber disks on drive shaft, as well as center bearing
New motor mounts
New transmission mount
New engine shocks
Front end alignment


The noise developed recently, about a month after the most recent work which was new ball joints, rotors, and wheel bearings.

The noise sounds exactly like a bad ball joint, but it was a brand new TRW (OE), and I simply cannot get any play out of the ball joint when I lift the front end, use a bottle jack to "unload" the ball joint.. and wobble the tire..just simply no play!

I also tightened the spindle nut thinking maybe the wheel bearing was loose, but it seemed ok.

The only bushings on the front end i did not replace are the big lower control arm bushings...if this rubber was going bad, I dont think the symptom would be knocking sound over washboard type of road surface.

I tightened all bolts on the front end (calipers, etc....) just in case I left anything loose...all were tight. The car tracks well, no steering wheel wobble, and no notable tire wear pattern.

At this point, I am almost ready to throw in the towel, especially when I am paying close to $5.00 per gal. for fuel.

If a bad shock cannot be diagnosed with the car up off the ground, do I just replace it and hope that is the problem? And what if that is not the problem...bring the car into a shop and say just make the noise go away? What will that cost?

Any input would be greatly appreciated.

Baffled in Boston,

Mark

__________________
1984 300TD Wagon, 407,800 mi (current daily driver)
1985 300DT Sedan, 330,000 mi (gone to that great autobahn in the sky)

Suspension noises are tough. If you were to take it into a shop, a good one will put a device on your car that has several sensors (sort of like microphones) that they'll tack onto various points of your suspension. They'll then take it out onto the road and listen for the sound. Once it starts, they'll go through the various channels (with the different mics) in order to pinpoint where the noise is coming from. This is, I think, the best way to track down stubborn suspension problems because it leads the tech directly to the noise & where it's coming from so that he can work on the problem with the confidence that he's got the right component.

The problem is, of course, that this costs money to diagnose & also to then fix the problem - whatever it is they find. It's probably at least an hour's labor to diagnose.

__________________
Ich muss geisteskrank sein.

The 1983 300 SD: "Old Smokey" (Hilda) Quarter Million Mile Club

The 1986 420 SEL EURO: "¡El Conqístador!" (Helmut) Trunk Triangle Club

The 1995 Cadillac Coupe deVille: "Schlag Kaltluft" (Shaft)

Well I went a little further replacing springs and lower control arm bushings/eccentric pin too and found the same thing. I just checked, and the gorillas at the tire shop had 45psi in the right front tire. I dropped it to 28psi, drove a couple of blocks hitting some serious bumps and it seemed quiet. I was pretty puzzled since EVERYTHING was replaced, but sometimes its the simple things I guess. And the work of simpletons.

__________________
tgingrich
'83 300TD 282k
'83 300D 239k
'82 300SD 204k
DFW