Loping sound and feel, stops with brakes - PeachParts Mercedes-Benz Forum

imagesinthewind · #1 03-16-2008, 10:34 AM

81 300SD

Replaced brake pads yesterday and drove it 10 miles or so to a party.
A slight loping sound was present but really faint.
On the way home the sound began to get louder and harder.
The sound and feel stops when I depress the brakes but not when I
coast.
The pad replace went without incident it seems.

Anyone know what it could be?
The tires are new and fine. I cannot even think what would be making the sound. I figure if the sound started after the brake job and stops when the brakes are depressed then the sound is brake related.

Ideas?
Thanks!

barry123400 · #2 03-16-2008, 11:24 AM

Warped rotor or a rotor with quite a bit of runout in combination with a really sticky caliper piston? Just a thought. Anyways since the problem surfaced at the last thing you did it is more than likely involved. I would want to make sure the caliper pistons will slide into their cylinders without much resistance. Again a one side to the other side comparison is a good yardstick.
You moved the pistons to a new operating area when you installed the new pads remember. The rust on the new area of the piston now being used if present could bind on the seals. Just something I would check out and does not mean it might not be something else. Double check that the wheel bearng is not loose but since you did not have the rotor off it is probably okay. You can jack up each side and check or compare one side with the other. Check tire turning resistance and check for same amount of play in and out etc.

t walgamuth · #3 03-16-2008, 11:48 AM

x2....warped rotor.

Tom W

imagesinthewind · #4 03-16-2008, 06:07 PM

I'm hesitant to tell you all that the problem is solved.

I'm embarrassed. I'm stupid. I'm an idiot. I was in a hurry. I AM LUCKY.

I didn't tighten the lugs on the drivers side when finished with the brake pads.

I figured this out when the car started shaking so bad that I had to pull off onto a side street. I thought the tire had bubbled. When I got out of the car, the drives wheel was being held on by ONE lug nut, one was hanging out and one more revolution would have found it flying. I was lucky enough to find a third on the road about 15 feet behind my car at the stop.

I took one off the back wheel so each had four. When I got home I took two off the parts car so I have a full set on all wheels and I checked all lugs.

The really funny (but not really) thing is 3 miles before I pulled off I was going 70 on the hwy. I'm shakin my head now and it'll never happen again.
I'm lucky.

t walgamuth · #5 03-16-2008, 07:13 PM

I have done that before.

I had just done some work on the car IIRC, and we were driving somewhere and I felt this wobbly sound. My Mrs. says it sounds like you left the lug nuts loose. So I give her this "are you crazy?" look....and when I checked it was loose nuts!

It has happened to all of us I imagine.

Tom W