vibration when breaking

I have a 96 e230 and when I break I'm getting a vibration through the car. I thought this was the disks so I changed them (all) which solved the problem for about 1000 miles. The problem came back so I assumed that the
disks were faulty so I took them back and had them changed under warranty. However, again after about 1000 miles the problem came back. Someone suggested a 'stick calliper's so when I changed the disks again (third time) I pushed the piston out three or four times and then looked to move ok.
However, the problem is back again. The problem is really bad braking at around 60 so I had the wheel balance checked and its fine.
Before I take it into the dealer to have them look at it, is there anything anyone can suggest ?. ( I have checked and re checked the tightness of the bolts etc )
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Did you also change the pads when you changed the rotors? If not, that's why it keeps coming back.
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yes .. new disks and pads each time

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I had oversize tires on my 190e over winter and had a 'bad' shimmy when I hit speeds between 85 and 95 kph. After checking all was Ok I just lived with it and avoided these speeds or went through them quickly. I now changed tires back to normal and have the identical problem to yours. Shymming (vibration) when rapidly breaking from high speed. I believe it's the steering damper and intend to check for this.
cheers

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many thanks .. I will get this checked out
wrote:

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My 300SD is very sensitive to tire balance and/or position. I had a situtation where the wheels were pulled for inspection, but not rotated. Then I suddenly had a nasty vibration. All the wheels were then balanced twice, yet I still had a vibration problem. Finally, I jacked the car up and tried moving wheels around. When I switched one front to back the problem completely disappeared. I can't explain what happened, nor why your problem doesn't appear for 1000 miles, but rotating tires one at time is worth a shot and easy.
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Tires are excluded because you say the problem IS solved for the first 1,000 miles after new discs are installed. But, if only to exclude a possibility, they could be rotated.
So that leaves the only other rotating part; a warped disc will cause such vibration, the question is why does it occur?
Cheap, non OEM, discs are cheap for a reason - they warp.
A stuck caliper will cause a disc to warp from the heat of a dragging brake, so will a plugged brake hose cause a brake to drag.
If the car consistently pulls toward one side during braking, particularly on light applications of the brakes, suggests a clogged brake hose that no longer allows brake fluid to flow and so retards the release of its brake. Suggest you bleed each brake, not for possible air in the brakes but to see how much fluid is released by each wheel. That will suggest which brake hose is closed up, most likely one in the front.
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Don't forget that it can also be caused by the calipers which ride on these discs!

Exactly my thought. The calipers could be hanging ever so slightly, which could be providing over heating, and then warping of the disks. This is more likely with a caliper that is designed to slide (ie hydraulics on one side only), as the the side it hangs on will get all the extra friction/heat (uneven heat thus warping).

I would be surprised if it's a hydraulic issue, although that is a possibility. I would take another look at the calipers...
You should be buying brake parts wholesale by now ;~)
Marty
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stuck calliper = warped roters
the case, minus a few cans!
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What about possible worn suspension parts. Worn bushings can cause this problem, since it is only felt when breaking from higher speeds (I have seen this on Chevy's, fords, and an early eighties Mercedes.
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I have had this happen before when the brale pads develope a glaze. Hard pads when always used gently will develope a suface like glass. You might try making a few panic stops. I have also sanded the surface of the pad just enough to break the glaze. Put a sheet of sand paper perhasp 120 grit on a flat surface like a sheet of glass and give it 4-5 swipes. Be sure to clean the sanded surface thoroughly to remave any trace of the abrasive. If you are using soft pads this isnt going to help. Good luck
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Thanks for all the suggestions .. I now have a few things to try. ( I tried rotating the wheels but this made no difference )
( This is the real power of the internet .. sharing knowledge and experience )

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I 'vote' for the caliper too. Had exact problem on a Dodge Caravan. Changed rotors/pads. Good for a while then the vibration at braking came back. Finally changed one front caliper and that was more than a year ago. No more problem.
Oh, the heat was so intensive, I can feel one wheel was hotter than the other.
henry wrote:

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"" wrote: > I 'vote' for the caliper too. Had exact problem on a Dodge > Caravan. > Changed rotors/pads. Good for a while then the vibration at > braking > came back. Finally changed one front caliper and that was > more than a > year ago. No more problem. > > Oh, the heat was so intensive, I can feel one wheel was hotter > than the > other. > > henry wrote: > > I have a 96 e230 and when I break I'm getting a vibration > through the car. > > I thought this was the disks so I changed them (all) which > solved the > > problem for about 1000 miles. The problem came back so I > assumed that the > > disks were faulty so I took them back and had them changed > under warranty. > > However, again after about 1000 miles the problem came back. > Someone > > suggested a 'stick calliper's so when I changed the disks > again (third time) > > I pushed the piston out three or four times and then looked > to move ok. > > > > However, the problem is back again. The problem is really > bad braking at > > around 60 so I had the wheel balance checked and its fine. > > > > Before I take it into the dealer to have them look at it, is > there anything > > anyone can suggest ?. ( I have checked and re checked the > tightness of the > > bolts etc ) > > > >
Henry.... Your reoccurring brake problem is probably due to a bad contamination on the axel flange, where the inside machined part of the rotor mates up with. When ever changing the rotors, the original flange has received transfer of steel rust and oxidants :( from the old rotors, that build up on its surface. The new rotor must mate with the flange very very cleanly and flat, or else you will get a tremendous amount of "run out" (wobble) even though the rotor is new. The same thing applies to the inside of the aluminum cast wheel your MB comes with. A large flat medium file must be used to flat out the surface of the axel flange, along with some 320 wet dry sand paper to help clean the transfered oxidation off of all surfaces. Keep filing in straight strokes until the whole flange surface is shinny again. Use brake cleaner or kerosene to keep your field of view fresh. Do the same for the inside of the cast aluminum rim. If a new or freshly cut rotor is installed on a dirty flange, a wobbly pulsing braking action could soon appear. A frozen caliper will cause a large noticable heat build up on the affected wheel, so check for this by carefully touching the rim after a 2 mile or so drive. If one particular rim is super hot, get a new OEM replacement caliper from some on line parts distributor. Warped Rotors stemming from a sticky caliper this causing overheating, usually would occur in the rear, as they are thinner and more prone to warpage. Get a dial indicator with a magnetic base to check your rotors run out, you will probably see as much as 30 to 50 thousands on a new rotor, if your flange is dirty. This has to be checked on the inside surface of the rotor, as your rim must be installed to mate the rotor to the axel flange. Three to Five thousands is good, but as much as ten can be tolerated.... Never recycle used pads with new rotors. always start from scratch: New rotors or resurfaced rotors= new set of pads...... Dave....
"93" 300TE 4 matic 181,000
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