Poping/klunking noise from passenger rear of my 300D - PeachParts Mercedes-Benz Forum

cewyattjr · #1 01-31-2009, 04:13 PM

Mine is a '82 W123...

My daughter was sitting in the passenger rear, and could feel the noise right under her. It almost sounds like something is bouncing around loose on the pavement, or almost like popcorn, really a randomish pattern. The sound varies with speed. Sounds like from the axle or wheel and quite noticeable in the cabin.

After our 2 hour drive down to CT from Mass today it seemed worse, but I examined the passenger left wheel and did not notice smell or heat from the wheel or brake area. NOTHING dragging on the ground, but that's exactly how it sounded.

I guess my concern is that it might be related to the axle or drive shaft and whether I can make the 2 hour trip back home tomorrow

Thanks for suggestions!

Chuck

kerry · #2 01-31-2009, 04:25 PM

I'm not sure if it's a popping or pooping sound. Can't think of anything that would explain a pooping sound apart from an impolite passenger, but a popping sound could be the half shaft or a wheel bearing. Will it last two hours????? I'd probably give it a try if it were my car and I needed to get home.

cewyattjr · #3 01-31-2009, 04:35 PM

Ha ha! OK.. popping. As in like popcorn. Anyway, I tell you what... it's loud enough and sounds serious enough it about makes you want to poop. I guess my fear is that something like the drive shaft or axle or bearings might be at issue. We've had a lot of ice, and I thought, oh, maybe chunk of ice knocking around somewhere (?).

Possibly suspension??? That would be better... but I'm not noticing any bad suspension symptoms.

kerry · #4 01-31-2009, 04:52 PM

It's most likely the axle. Wheel bearings tend to give more of a grinding or whining sound. If the noises occur all the time and are really loud, it might be a good idea to get it fixed before driving it again. If it only makes the noises when going around turns or over bumps, I'd probably try driving it home.

rhodes2010 · #5 01-31-2009, 05:35 PM

Noise is only while in motion ?
I am thinking bearings.
At all times and not occasional,
does it vary with speed ?

Lift each wheel, turn by hand and listen and feel, a bad bearing
will tell you it is there.

Lift whole read end at the pumpkin and turn rear wheels.
Listen for driveshaft center bearing.

I have put a couple hours on a bad bearing...
but not a bad flex-disk, I only got an hour or two tops out of that.

cewyattjr · #6 01-31-2009, 05:41 PM

An if the flex disk or bearing goes while I am on the highway... how bad???

t walgamuth · #7 01-31-2009, 05:44 PM

It does not sound like a flex disc to me. I am with Kerry....half shaft. They can make a lot of racket but will endure a lot. I would proceed with caution. Take the back roads....the slower you drive the longer it will endure.

Good luck.

Jerry_Mullen · #8 01-31-2009, 05:48 PM

Look under the rear of the car and check if you have a torn rubber boot on one of the axle half shafts (the outer in particular). Then grab the axle shaft and try sliding it back and fourth several times (towards the differential then towards the rear wheel) What happens when the boot tears is the grease spins out and the joint gets dry and doesn't slide easily anymore, this causes play on the CV joint, moving the half axle sometimes temporarly tightens things up. It doesn't hurt to squirt some oil into the joint also. If this works, you can safely drive home.

Another thing to look at is the center driveshaft bearing support, when that bearing goes, it makes a horrible noise more when you are moving slowly.

Good luck!

cewyattjr · #9 02-01-2009, 09:25 AM

Quote:

Originally Posted by t walgamuth

It does not sound like a flex disc to me. I am with Kerry....half shaft. They can make a lot of racket but will endure a lot. I would proceed with caution. Take the back roads....the slower you drive the longer it will endure.

Good luck.

Update -- I have the regular MB tire jack, and picked up the passenger rear. There is a good bit of play in the wheel, I can get some rotation each way and can see the drive shaft move some as well. Expected? Klunking pretty regularly now, so am thinking about having AAA (Plus!) take the car from CT back to Worcester, Mass where my MB mechanic is.

A "half-shaft" is what... axle?

Thanks guys.

Chuck

kerry · #10 02-01-2009, 09:50 AM

Half shaft is the axle on one side. Movement in wheel, axle and driveshaft is normal. Did you try sliding the axle in and out? Don't get under the car while raised only on a jack. Use a jackstand.

t walgamuth · #11 02-01-2009, 12:28 PM

If you have rocking play in the wheel you have a bad a arm. The only play at the wheel should be rotationally. If you have any other play better not drive it at all. The wheel could come off and that would not be pretty!

ON the half shaft play in and out is normal, up and down is not.

Jerry_Mullen · #12 02-01-2009, 01:18 PM

Did you notice if the axle boot was torn? If it is you will need a new axle shaft, again you can stop the klunking long enough to get it home by squirting some oil through the torn boot onto the CV joint and working the axle shaft back and fourth, this will allow the CV joint to preload again, try it.

cewyattjr · #13 02-01-2009, 01:42 PM

Quote:

Originally Posted by kerry

Half shaft is the axle on one side. Movement in wheel, axle and driveshaft is normal. Did you try sliding the axle in and out? Don't get under the car while raised only on a jack. Use a jackstand.

Not even jacked up, since I don't have my stands with me, I *can* get some sliding movement on the axle between the boots -- it takes some effort but will move back and forth... so maybe rotational play is normal, but lateral movement? That can't be right. I can't drive two blocks now without bang-bang...

The boots seem in good shape, though.

cewyattjr · #14 02-13-2009, 09:18 PM

Just a follow-up. I had the car towed to my indie mechanic who has worked on this car off and on for a couple of years now. Initially, I understood that he repacked bearings in the rear, and replaced a set of completely worn brake pads. Did some lube as well. Car was quiet for a day, and then within 100 miles, noisy again. Starts out with a quiet and occasional klank and then over the next few days gets louder and louder until heads on the street turn -- sounds like some african rhythms.

OK, so I take it back. This time he puts in a new bearing kit and for whatever reason says that he has to mess with the axle a good bit and put in some new gear oil. Again, quiet for some miles and now it is getting louder again.

My take is that he's avoiding replacing the axle. So far I've shelled out a bit over $500, and the noise is still with me. I guess I would've rather just had the axle replaced. I actually think it is a good shop and they were trying to save time/money. For now, this MB is going to take a time out in my driveway for a while, and I'll run the TDI for a bit.

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