Hi all,
I recently changed the front bearings, brake discs and brake pads in my 1983 300D-T and everythings works pretty well, but after moving forwards, when I put the car in reverse and hit the brakes while the car is rolling, there is a slight initial clunk. It kind of sounds like something is shifting, like the caliper or pads or something. I took a look at the caliper bolts and they're on pretty tightly, so I don't think the caliper unit is shifting, but could it be the pads? It only happens once. I didn't change the four pad pins that go through the pads and caliper housing. The brakes work great (I just took the car on a 1000 mile trip) and the sound only happens once. It's as if the pads shift, seat themselves, and the sound goes away. I just want to fix it because the sound is pretty alarming to the passengers in the car. Oh, and it's not loud, it's pretty gentle, but can definitely be heard and slightly slightly felt. Thanks for the advice. If I can clarify any questions you have, I will as soon as possible. However, after tomorrow morning, I probably won't be at a computer for four days. Anyway, thanks again.

Alex

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1983 300D 182K miles
1994 Toyota Landcruiser 127K miles
2002 BMW 330ci Convertible 24K miles
1999 C43 AMG 81K miles

Brake strut bushings? Where are these located? are they hard to replace? If they're not absolutely critical right now, I probably won't do it for a while because I need a break from that car. Are these bushings part of the suspension? Thanks for all the answers =)

Alex

__________________
1983 300D 182K miles
1994 Toyota Landcruiser 127K miles
2002 BMW 330ci Convertible 24K miles
1999 C43 AMG 81K miles

AKA Strut Rod Bushings. You need to get the car up in the air safely with the wheels hanging, then push, bang, shake, pull, etc. fore and aft on the wheel. If the strut rod bushings are indeed the culprit, this is a bit of a job. The bolts that hold the strut rod to the lower control arm are underneath the spring.

IF this is the problem, you may be better off letting a properly equipped shop take care of this one.

These bushins location: On either side of the car there is a rod that goes generally from the bottom of the lower control arm rearward to a round mount at the lower, inner portion of the front fender well. If this is indeed your problem and it is indeed so bad as to alarm passengers, you should check this soon.

Good luck,

You may also want to look at the lower control arms, I had the same problem when I first got my 85 300 and it turned out to be a worn lower control rod. Two years later, I just replaced the "Castor Bushings," which is what I think the other members are talking about.

Although the caliper bolts may be tight, they may be bottomed out. This happened to me in my '79 300SD. Putting a washer under the head of the caliper bolts fixed the problem for a cost of about 20 cents for the washers. Its worth a try. ~~~~~~~~~~~~~~~~~~~PEH~~~~~~~~~~~~~~~~~~~~

Hmmm..... I just had the "works" done to the front end of my 300D so I don't think it's those bushings although I'm not a hundred percent sure they were replaced when the work was being done. I'll try out the washer idea since it's cheap and won't take a long time. Hopefully it'll work out. If not, I'll have someone look into those bushings. Thanks everyone

Alex

__________________
1983 300D 182K miles
1994 Toyota Landcruiser 127K miles
2002 BMW 330ci Convertible 24K miles
1999 C43 AMG 81K miles

I've been driving around with this clunking for about two weeks (since I first posted my problem). I tried adding washers to the bolts holding the calipers to the hub, and that didn't really fix anything. My uneasy feeling is this: I had the "works" done on the front end a year ago, so this clunking shouldn't be the result of bad bushings. Also, it clunks when I brake in reverse, but it doesn't "clunk" back into "position" until I brake rolling forwards. If it were indeed the bushings in the front-end setup, wouldn't it "clunk" back without me having to brake rolling forwards? Also, this coincidentally just started happening after I replaced the brake components and bearings. This is all very puzzling to me. I really think the sound is a result of shifting brake pads) moving back and forth with different directional rotation). Is this possible? Otherwise, the car is running better than it ever has (basically as a result of discovering this message board). Thanks for the input.

Alex

__________________
1983 300D 182K miles
1994 Toyota Landcruiser 127K miles
2002 BMW 330ci Convertible 24K miles
1999 C43 AMG 81K miles

Oh, I forgot to mention also that there is no rattling, clunking or other "looseness" sounds coming from the front end while I'm driving. It's all very tight and solid while driving, even when going over un-even pothole ridden NY pavement.

Alex

__________________
1983 300D 182K miles
1994 Toyota Landcruiser 127K miles
2002 BMW 330ci Convertible 24K miles
1999 C43 AMG 81K miles

I guess what I was trying to say, was that I was puzzled because it should "clunk" back by itself without the need for braking while rolling forwards from all the suspension movement on the road. Does that make any sense? (my wording may not be that clear). I mean, I will go over very very uneven pavement and it still won't "clunk" back until I break, which leads me to speculate that the problem isn't in the suspension components because they are shifting all the time.

Alex

__________________
1983 300D 182K miles
1994 Toyota Landcruiser 127K miles
2002 BMW 330ci Convertible 24K miles
1999 C43 AMG 81K miles

What brand of brake pads did you use? Did they appear to match the size and shape of the old ones? I'm partial to ATE brand. I found they actually sweep more of the rotor than whatever was in there before (they had an MB emblem on them)

I always suspect the most recent repairs as the cause of new noise.

You may be able to narrow down the noise by jacking up one side (please use jackstands and don't rely on the MB jack) and spinning the wheel as fast as you can by hand, and having an assistant step on the brakes sharply. From your description it appears to be the transition from forward to reverse, so spin the wheel first in one direction and then the other.

Being closer to the wheel may help you decide where the noise is coming from, if you can repeat it.

Next, if the noise is repeated by the above test, take off the tire and observe the brake components as you spin the rotor by hand and have the brakes applied. You may be able to spot something moving. You should have spring clips against the pads that are held in place by the pins. Are they missing? (Haynes manual calls them "anti-rattle" springs.)

I don't really think this test will necessarily find your problem, but its a start. Keep us posted on what you find.

Ken

Ok, will do. I'll probably take the time to have a look on tuesday. Thanks for the input, I'll post any new observations or developments

Alex

__________________
1983 300D 182K miles
1994 Toyota Landcruiser 127K miles
2002 BMW 330ci Convertible 24K miles
1999 C43 AMG 81K miles

I should also mention that the clunk isn't terribly loud and you can't hear it with th radio on. Also, it only comes twice: once the first time you apply the brakes going in reverse, and the second time when you apply the brakes going forwards. I never hear it again. Anyway, thanks, hopefully I'll get a chance to jack up the car tomorrow

Alex

__________________
1983 300D 182K miles
1994 Toyota Landcruiser 127K miles
2002 BMW 330ci Convertible 24K miles
1999 C43 AMG 81K miles

Greetings Bill,

From the posts I have read in this thread I believe I have the same problem on the drivers side of my Benz. These bushings you speak of, what is the proper term for them? Is it the wheel end or the frame end that contains the bushing? Looks to me like the wheel end. Any reason why a DIY'er can't do it and save some bucks in the process? Any special tools required to accomplish this task? I'm not up to paying someone cold cash for something I can do myself? So have you done it yourself with moderate ease without the cuss words, what the heck I can live it up and break a few rules myself. I'd just like to rid myself of this annoying clunk as well. Don't happen to have the part number to the bushings do you?

Charles

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"Tell me and I will listen, Teach me and I will learn, Show me and I will accomplish, Involve me and I will succeed."
'84 300SD 256,000 Gold on Brown (Mileage Award)
'86 300E 246,000 Blue on Tan

Well, I finally had a chance to take a look at the suspension front end of my car. I vigorously shook the various control arms and suspension parts and nothing really moved that wasn't supposed to move so I guess that kind of rules out the bushing problem (or does it?). I did notice however that the holes in the brake pads are larger than the diameter of the pins that go through them. Is it supposed to be that way? Also, when I installed these pads, I didn't install shims beacuse it looked like they were already on the pads themselves (they looked almost glued onto the pad backings). SOmeone asked previously what brand pads they were and I honestly don't know. I got them at a Mercedes dealership so I assume they're correct. I did drive around a little bit with a critical ear and the windows down. There is a noticeable chattering sound when I lightly hit the brakes (and I mean very lightly, so that the pads are only exerting a little pressure on the rotors). Almost sounds like something was rattling in the c

__________________
1983 300D 182K miles
1994 Toyota Landcruiser 127K miles
2002 BMW 330ci Convertible 24K miles
1999 C43 AMG 81K miles

Almost sounds like something was rattling in the caliper housing. It's not too out of the ordinary. I think all cars do it, just mine does it a little more.
Also something to maybe think about. When I installed new brake discs, is it possible that I didn't fit the hubs onto the rotors correctly? I honestly do not think it is that, but who knows, it's worth mentioning.
It's very difficult to describe what I noticed and heard in words, so if any of you have any specific questions, I will definitely answer them as best I can.
Thanks everyone for the help. This message board has proven to be an invaluable resource.

Alex

__________________
1983 300D 182K miles
1994 Toyota Landcruiser 127K miles
2002 BMW 330ci Convertible 24K miles
1999 C43 AMG 81K miles