STILL -- Thunk thunk thumk from passengers rear - PeachParts Mercedes-Benz Forum

NC Benz · #1 07-03-2007, 03:48 PM

ermmmm..... not the passenger, but the passenger side of the car.

Since I have had this car.. at about 25 MPH I get (and can feel) a thunk thunk thunk. It is stronger when I turn left (putting more pressure on the passenger rear wheel).

This morning I was hearing (and feeling) metal scraping on that area. I stopped at work for an hour and it went away.

I took it to a repair shop to look at it. No boots are torn.

This is the second shop I have had look at it. One wanted to replace BOTH half shafts. This one just said take it to a dealer (and wanted to charge me to look at it.. no thanks)

I cant see anything rubbing or hitting. I looked at the sway bar and that seems OK as well.

Thoughts????

Am I nuts???

(No answers from the peanut gallery!!!)

MattBelliveau · #2 07-03-2007, 03:51 PM

Quote:

Originally Posted by NC Benz

ermmmm..... not the passenger, but the passenger side of the car.

Since I have had this car.. at about 25 MPH I get (and can feel) a thunk thunk thunk. It is stronger when I turn left (putting more pressure on the passenger rear wheel).

This morning I was hearing (and feeling) metal scraping on that area. I stopped at work for an hour and it went away.

I took it to a repair shop to look at it. No boots are torn.

This is the second shop I have had look at it. One wanted to replace BOTH half shafts. This one just said take it to a dealer (and wanted to charge me to look at it.. no thanks)

I cant see anything rubbing or hitting. I looked at the sway bar and that seems OK as well.

Thoughts????

Am I nuts???

(No answers from the peanut gallery!!!)

Change both half-shafts. My car was doing the same thing (intermittantly) for the first year I owned it. The noise never stuck around long enough to have it properly diagnosed. Changed out the HS's, noise has yet to return.

d.delano · #3 07-03-2007, 03:55 PM

If you have a thump thump in the rear, and the boots aren't torn, it doesn't necessarily mean you don't need new axles. And- if you replace one, you should probably replace the other as a matter of course, or you will find out that the other one wants replacement too in short order. That noise and those symptoms- they are indicative of bad axles. The reason it stops when you stop for a while is that the metal cools in the CV joint, thereby increasing the internal tolerance. As you drive, it heats back up and gets tight inside there and starts making the racket again. I have been through this, and you need new rear axles, no doubt about it. Buy CVJ rebuilt axles or new OE, don't risk anything else.

rebreath · #4 07-03-2007, 03:57 PM

could it be the driveshaft somehow?mount,flex joint maybe

kerry · #5 07-03-2007, 04:05 PM

lubricating my half shafts solved the problem on mine.

NC Benz · #6 07-03-2007, 04:07 PM

Quote:

Originally Posted by kerry edwards

lubricating my half shafts solved the problem on mine.

Is there a "how to do" on this procedure?

Thanks!!

kerry · #7 07-03-2007, 04:15 PM

Quote:

Originally Posted by NC Benz

Is there a "how to do" on this procedure?

Thanks!!

I'm sure there is. I took my car to an indy because I thought it needed wheel bearings. They diagnosed the dry half shafts. It was clear they loosened the clamps on the boots. I assume they injected some kind of grease in there. They also adjusted the height of the SLS.

NC Benz · #8 07-03-2007, 04:18 PM

Quote:

Originally Posted by kerry edwards

I'm sure there is. I took my car to an indy because I thought it needed wheel bearings. They diagnosed the dry half shafts. It was clear they loosened the clamps on the boots. I assume they injected some kind of grease in there. They also adjusted the height of the SLS.

OK not trying to be a tard boy here... so basically lubing the half shafts is basically adding (injecting) some lube into the CVs?

THANK YOU!!

d.delano · #9 07-03-2007, 04:20 PM

kerry edwards is also correct- if the boots aren't torn, maybe you don't absolutely need new halfshafts right now. Get a hypodermic needle from somewhere, and fill it with hypoid gear oil. Inject the oil into the boot, the puncture should self-seal. I think this is what people have done in the past- one would assume that the CVs are packed with grease, but no- it is a liquid oil that's in there originally.
I only said get new ones because eventually you will have to get them- I don't believe re-lubing the CVs after you hear that thunk noise will last forever. Good luck though

NC Benz · #10 07-03-2007, 04:23 PM

Quote:

Originally Posted by d.delano

kerry edwards is also correct- if the boots aren't torn, maybe you don't absolutely need new halfshafts right now. Get a hypodermic needle from somewhere, and fill it with hypoid gear oil. Inject the oil into the boot, the puncture should self-seal. I think this is what people have done in the past- one would assume that the CVs are packed with grease, but no- it is a liquid oil that's in there originally.
I only said get new ones because eventually you will have to get them- I don't believe re-lubing the CVs after you hear that thunk noise will last forever. Good luck though

Sounds like a fun project. Guess I better head over to the shady side of town to pick up some needles.......

Stevo · #11 07-03-2007, 04:29 PM

I have never done this but my indy friend has mentioned "injecting lub under the boot". I would give it a try while I shop for a couple axels

vstech · #12 07-03-2007, 07:13 PM

Quote:

Originally Posted by d.delano

Inject the oil into the boot, the puncture should self-seal.

Um, self seal? forget that!
if you puncture the boot, it will fail rapidly.
if you loosen the small end, fill with lube, and replace it with a hose clamp it will be fine tho.
good luck.

rsmartin · #13 07-03-2007, 07:30 PM

did u replace sway bar links? very inexpensive fix to a rattle in the rear commonly experienced.

NC Benz · #14 07-03-2007, 11:42 PM

Quote:

Originally Posted by rsmartin

did u replace sway bar links? very inexpensive fix to a rattle in the rear commonly experienced.

That is definitely one of the things I looked at. They seem ti be OK.

pawoSD · #15 07-04-2007, 09:35 AM

Quote:

Originally Posted by NC Benz

That is definitely one of the things I looked at. They seem ti be OK.

They can appear ok but still be sloppy and worn out. I'd consider replacing those first, they only cost like $11-12 Both of our cars made clunking sounds, went away with the new sway links.

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