Rear suspension pinging noise
 

'87 300SDL - 230K miles

Several months ago I had a disturbing pinging noise that occurred when I went over speed bumps. Made a very pronounced "twang/pop" Really was a cross between a spring noise and someone tossing a golf ball inside the trunk.

Had it checked out and a rear shock was leaking, plus a lower control arm had a rust hole in it (not bad). Replaced the shocks around Christmas and it went away. Until about 2 weeks ago. Started coming back. First over speed bumps, then not so consistantly. But it might do it 2 or 3 seconds after a bump. And of course, not every time.

Concerned, I took it to my Indy today who heard it a little (of course it was not consistant when I needed it to be). We put on a lift and did not see anything earthshattering. To me, it sounds like a broken spring, but there was no evidence of that. There were some small boots inside the rear wheels that were cracked and open and they recommended replacing these, but indicated it was not critical.

So not sure what it is. Anyone have a similar noise and fix it?

Just a thought...
 

Since it happens kind of after the bump and since the boots on your axles are broken is it possible that you got some rocks or other such items thrown into the boots? Then at low speed you go over a bump and it tosses on into the axle joint? The noise you hear is the rock or whatever being crushed and the sound of metal crushing it?

Kinda fishin here. The boots are not critical right now but they will be. With the grit etc that you pick up off the road from driving it will wear the axle joints inside the boots out pretty fast. That is if they are open and not just cracked.

You might try replacing the sway bar links. Mine sounded like I had a load of scrap iron in the trunk when I went over a bump. Now it is quiet. It cost $8.50 per side, and took about an hour. Remove the rear tires and you will see the links. They are plastic about six inches long and sort of "S" shaped with a rubber bushing at each end. If yours are worn out, the rubber will be completely missing. You will need two 17 mm wrenches; one must be open ended. Good luck.