Clunking - PeachParts Mercedes-Benz Forum

Adriel · #1 06-15-2013, 01:58 AM

In a prior thread, was figuring out why there is a clunk when the engine shuts off. I hadn't connected it to the suspension until today when I have the front wheels are off the ground. Twice now I have shut the engine off, and no clunk!

That could explain why I hear clunking during acceleration and deceleration. It is also intermittent, but mostly there. Couple times pressed on a curb with the wheel turned and clunked. I am almost ready to throw in the towel and rebuild what is bad on the suspension rather than fiddling with this and that. This month has been rough (based a financial decision on a worthless check, live and learn...). Any thoughts, especially plan of action?

Thank you so very much in advance!

Stretch · #2 06-15-2013, 02:09 AM

This problem reminds me of a fantastic video that was made of a weird clunking sound made when turning

http://www.peachparts.com/shopforum/diesel-discussion/334165-front-suspension-noise-video.html

It turned out to be engine mounts

I'm sorry to push you back towards engine mounts again.

A good way of checking suspension noise is to put the front wheels on slip plates and then bounce the car up and down to help you track down the part that's giving you trouble.

Adriel · #3 06-15-2013, 02:14 AM

Quote:

Originally Posted by Stretch

This problem reminds me of a fantastic video that was made of a weird clunking sound made when turning

http://www.peachparts.com/shopforum/diesel-discussion/334165-front-suspension-noise-video.html

It turned out to be engine mounts

I'm sorry to push you back towards engine mounts again.

A good way of checking suspension noise is to put the front wheels on slip plates and then bounce the car up and down to help you track down the part that's giving you trouble.

Thank you so very much!

I know that video well! That is what led me down the road of mounts. I can rock the engine back and forth with no noise while on axle stands, so that has no meaning?

What are slip plates?

Stretch · #4 06-15-2013, 02:18 AM

Well I guess you have to push the engine really hard one way or the other to get a clunk...

...if you're sure it isn't motor mounts then this could be for you.

Slip plates

Taken from here =>

http://www.peachparts.com/shopforum/2539500-post3.html

Adriel · #5 06-15-2013, 02:32 AM

Tried to get a video, but phone is acting strange and the camera is somewhere safe...

I was still able to get a lesser version with the body on axle stands! The tie rods do make a unhealthy amount of noise, but seems like something else too, like the idler.

Is there supposed to be rubber between the stops and the body? There is a hole in the mount, so my guess is yes. But, if so, are they still available?

Consider also I can get the same noise when pushing on the tire with it turned against the curb, like when turning into a parking stall. Not as loud, but still, now to me sitting, listening, feeling, and thinking, going to say best bet is tie rods. I know they are less then 75,000 miles and were good 5,000 miles ago according to Tram, but a inch and a half of wheel play or about half to an inch at the center? That is most likely out of specification! Also, idler bushing is dry and chunking...

Unless, it is easier to replace the mounts? I thought the engine had to be removed?

Stretch · #6 06-15-2013, 06:06 AM

Take some pictures of the rubber parts on the suspension if you can - especially the lower control arm and upper control arm mounting points on the body. All worn rubber parts will eventually make clunking noises but don't fall into the trap that because it is old it should be chucked away. The quality of some parts is dreadful these days - you can read many a "it only lasted 2 hours" horror stories here and on BW.

This is particularly irritating if you take the car to the dealer for an alignment only to find that you need to go back again because a new part died after driving around the block once...

Mölyapina · #7 06-15-2013, 06:59 AM

My 'SD does this too, and it has new motor mounts but no engine shock. It also needs a valve adjustment.

Stretch is in the Netherlands, so I understand why he's posting now... but Adriel! You need to get to bed!

Hah -- it appears that Squiggledog was on the forum at this time, too...what is it with you Arizona guys?

toomany MBZ · #8 06-15-2013, 07:39 AM

Yes, inspect the all front end components for obvious wear.

Replace what is necessary, then get a front end alignment.

Adriel · #9 06-15-2013, 11:47 AM

Quote:

Originally Posted by Stretch

Take some pictures of the rubber parts on the suspension if you can - especially the lower control arm and upper control arm mounting points on the body. All worn rubber parts will eventually make clunking noises but don't fall into the trap that because it is old it should be chucked away. The quality of some parts is dreadful these days - you can read many a "it only lasted 2 hours" horror stories here and on BW.

This is particularly irritating if you take the car to the dealer for an alignment only to find that you need to go back again because a new part died after driving around the block once...

So I have some pictures! Now I am seeing even more interesting things! You all have your work cut out!

This is going to take a while...

Part one.

Adriel · #10 06-15-2013, 12:04 PM

Part two.

Adriel · #11 06-15-2013, 12:06 PM

Part two.

Has disappeared I hate Peach sometimes!

Adriel · #12 06-15-2013, 12:15 PM

Part three, as apparently part two did post!

toomany MBZ · #13 06-15-2013, 12:17 PM

Reappeared!

The only issue I can see is in pic for of part two, the UCA inner bushings could use replacement, just replace the whole thing. Even that doesn't look too bad.

Pic one part two, the lower bushings may need attention, but overall, doesn't seem to be terrible.

May be the guide rods are shot.

Adriel · #14 06-15-2013, 12:22 PM

Quote:

Originally Posted by toomany MBZ

Reappeared!

The only issue I can see is in pic for of part two, the UCA inner bushings could use replacement, just replace the whole thing. Even that doesn't look too bad.

Pic one part two, the lower bushings may need attention, but overall, doesn't seem to be terrible.

May be the guide rods are shot.

Thank you so very much for the help!

What about the crazing on the upper ball joint, the torn tie rod end boots, the crumbling idler bushing (hard to get a picture of it and stay somewhat clean), and the large chunks missing behind the upper ball joints on the control arms? I especially do not like the metal to metal contact! I am thinking that might be a noise maker?

Lower bushings are supposed to be new. Might need some mineral oil?

Adriel · #15 06-15-2013, 12:27 PM

Quote:

Originally Posted by Jooseppi Luna

My 'SD does this too, and it has new motor mounts but no engine shock. It also needs a valve adjustment.

Stretch is in the Netherlands, so I understand why he's posting now... but Adriel! You need to get to bed!

Hah -- it appears that Squiggledog was on the forum at this time, too...what is it with you Arizona guys?

I plan to do an adjustment, just felt other things were more important, especially when it seems it wouldn't help the clunking.

I normally go to bed by eight/sunset and up by seven, like this morning. Though normally need at least 10 hours to try and sleep. But alas, once again was talking to Tram, then my Aunt wanted to chat for an hour or more, then got a reply, so wasn't in bed until midnight. I can never seem to catch up on my sleep and after several months, getting interesting.