HELP!!! Something has finally broken down! - PeachParts Mercedes-Benz Forum

rino · #1 02-27-2007, 07:36 PM

This is in reference to what was discussed earlier here (even though it might be something entirely different, but I doubt that):

Rumbling noise in back of 240D when making turns

I had made everything ready for lifting the car and placing it on stands tonight, in order to look into the brakes and various other items under the car likely to be responsible for that rumbling/clunking noise from the rear... was (and am) going to do it tonight...

About an hour ago I was driving the car (luckily I was just about half a mile from where I live) and suddenly there started this constant loud grating noise coming from the rear.
I was going about 25 mph, and the noise was so loud and alarming that I pulled immediately to the side of the street and took a look under the car (it sounded like something had partly detached from the bottom of the car and was being dragged on the pavement)... But nothing was hanging and everything looked normal. I drove the car VERY slowly (still with the noise on) to my garage. I am going to take a more in-depth look tonight.
Now the car makes this noise, constantly, whenever it is moving. It is a loud rasping noise that sounds like metal grating against metal. My first thought is that one of the rear brakes might be causing it.

Please advise... I hope I didn't cause a huge amount of damage...

Thanks,
Rino

JackG · #2 02-27-2007, 07:50 PM

check your axles

diametricalbenz · #3 02-27-2007, 07:53 PM

Probably so, the boots and bearings have probably gone completely dry and are scraping.

TMAllison · #4 02-27-2007, 10:56 PM

When you get teh rear up on jack stands put it in nuetral and rotate the tires and drive shaft until you can confirm where the nosie comes from.

Brakes, half shafts (axles), diff are most likely IMO.

#5 02-28-2007, 07:08 AM

I really wish I could tell you what is wrong, but that is virtually impossible by simply reading a description. The ONLY way you will know is to start turning, shaking, prying or whatever until you find it.

As mentioned by a previous poster, start by getting the rear wheels in the air safely so that you can rotate everything and find the culprit.

I have maintained right at 1 million miles of 240D's and probably a little over 100,000 miles of 300D's personally owned and have NEVER had to touch a rear axle shaft for failed boots, joints or ANYTHING. I will be surprised if you find the problem there.

It could be something as simple as running over a piece of wire and getting it wrapped around the driveshaft or one of the axles.

Keep us posted,

lefttownlance · #6 02-28-2007, 12:44 PM

maybe the exshaust pipe has settled in to the drive shaft? something to look at.

vstech · #7 02-28-2007, 12:51 PM

Not to worry rino, just get the car safely lifted and secured (did you end up getting those 12 ton jackstands?) like larry and lance have said, it's probably something simple.
John
with the car in neutral, you may not be able to rotate the driveshaft from the tire. usually, the opposite tire will spin freely the opposite direction, so you may have to crawl under the car and manually turn the drive shaft.

rino · #8 02-28-2007, 12:56 PM

I finally got to get the wheels in the air last night and began with a brake inspection. The front brake setup looks just fine, with the brake pads looking like new (I was surprised, since I've been driving the car for two years - about 5,000 miles - and I have never done any brake maintenance on it). Though the wheels, it seems to me, are not spinning totally free... there seems to be some slight brake dragging there, but I am not sure 100%, since this is the first time that I look into this type of maintenance.

BUT... THE REAR BRAKES ARE A BIG MESS! and I think I have found the culprit right there!

First of all, the brakes are heavily dragging on both sides. When I tried to spin the rear wheels (gear in neutral, parking brakes off), there's no free spinning whatsoever, the wheels are almost stuck and on the right side there's that grating sound (no wonder, then, that the car has had a low fuel mileage all along - around 20 mpg...) Moreover, on the rear left brake setup there's a segment joining two balljoints (I have no idea what that thing is or what it is called... it's not in my Haynes manual) which is completely detached on the lower end. The same segment in the rear right brake setup is still attached on both ends but the lower attachment to the balljoint is visibly damaged and about to get detached. Can someone suggest a site that gives a better description on brakes than my manual does, where I can learn about those "balljoint segments", possibly with pictures so that I can get a better idea of what the normal setup should look like?
The rear brake pads are worn out on both sides, but more so the inside pads, which are now about 2mm. So I am going to get a whole new set of pads for the rear and replace them.

What else should I do? What about those "balljoint segments"? (please excuse my not being able to use a better terminology at this time)

Hopefully, fixing the brakes will also take care of that horrible grating noise...

Rino

vstech · #9 02-28-2007, 01:04 PM

wow!
it sounds like you have some bad calipers back there, I would replace them for sure! inspect the rotors, and verify they are ok before you re use them, new ones are not expensive. don't bother getting them turned if they are scored.
I don't know the back end of the sedan very well, I could jack up the parts car I have and take some pictures for you, but I am sure someone here has better suggestions. surely to pete, there is a member or two in the L.A. Area willing to give you a hand... I would be happy to if you were about 3000 miles closer.
John

winmutt · #10 02-28-2007, 01:10 PM

frozen calipers are very common. pull one off and try to compress the piston back in. if it doesnt compress, remove the brake line and try to compress again. sometimes the brake hoses will collapse internally so if it compresses after removing the hose then your hose is bad.

rino · #11 02-28-2007, 01:10 PM

Quote:

Originally Posted by lefttownlance

maybe the exshaust pipe has settled in to the drive shaft? something to look at.

I just checked right now... no, it has not. I am still missing two muffler hangers and the exhaust pipe is still slightly lowered. I am replacing all four.
I am ordering all this stuff online... Rear brake pad set, muffler hangers, also need an air filter, the two fuel filters... I am waiting to see what else I need for the brake setup, then I am going to place the order.

Rino

Stevo · #12 02-28-2007, 01:20 PM

"balljoint segments"? could those be the "sway bar links", if so thats a cheap and easy fix. Keep your fingers crossed.

rino · #13 02-28-2007, 01:20 PM

Quote:

Originally Posted by vstech

(did you end up getting those 12 ton jackstands?)

Hi John, no, I got the smaller ones, which I am using along a 2.5 ton floor jack...
This setup works perfectly, and it is not as space consuming as the larger devices... I have to work with the limited storage space I have at this time, and these items suit me just fine.

Quote:

Originally Posted by vstech

wow!
it sounds like you have some bad calipers back there, I would replace them for sure! inspect the rotors, and verify they are ok before you re use them, new ones are not expensive. don't bother getting them turned if they are scored.
I don't know the back end of the sedan very well, I could jack up the parts car I have and take some pictures for you, but I am sure someone here has better suggestions. surely to pete, there is a member or two in the L.A. Area willing to give you a hand... I would be happy to if you were about 3000 miles closer.
John

OK, I'll have to wait until tonight to inspect the rotors. What is the stuff that I described as "balljoint segments?" Do I need to replace (obviously) those as well?

Thanks,
Rino

rino · #14 02-28-2007, 01:22 PM

Quote:

Originally Posted by winmutt

frozen calipers are very common. pull one off and try to compress the piston back in. if it doesnt compress, remove the brake line and try to compress again. sometimes the brake hoses will collapse internally so if it compresses after removing the hose then your hose is bad.

OK, I'll try that tonight. Thanks.

Rino

vstech · #15 02-28-2007, 01:23 PM

more than likely those are the antisway bar mounts, hopefully anyway.
since you were able to drive the car straight. if it is the ball joints back there, not fun I bet. but I will know more tonight when I get home to look at my parts car.
John