Braking Vibration

[Leemc2008]

Hi all

Getting a massive vibration through the brake pedal/whole car when I slow down!! The discs appear to be in good condition and the pads look almost new!

Happens from any speed.. the vibration in the pedal is literally pushing up foot back up. Doesnt pull left or right..

As it can be felt through out the whole car, wouldnt expect 4 warped discs normally!

My car is 94 C280 (W202)

 

[BlackC55]

If it comes through the pedal I suspect it is just the front discs either warped or corroded in one place.

 

[Leemc2008]

I'll whack on some new ones if I can get some on Saturday morning.

 

[Dieselman]

Before doing that check the run-out. Nearly all warped disks aren't warped at all, they have friction material build up causing grabbing.

Try a drive with your foot hard on the brake and the other full down on the accellerator. If things improve after that the disks just need a clean.

 

[Leemc2008]

Anything is worth a try.. cheers for the reply.

 

[Alps]

warped discs defo, my discs looked good too, and over a period of 6 mnths got worse, in the end new discs and pads, now perfect!

obviously try the things suggested above first, but more than likely warped!

 

[Dieselman]

Did you try checking the runout and cleaning them up before changing them.?

 

[Alps]

Did you try checking the runout and cleaning them up before changing them.?

yep, my indi skimmed the pads, and brushed off all the loose rust , even done a trackday with them! , still the same, changed them and hey presto, all fixed!

gave me a reason to change to greenstuff pads at the same time too!

 

[kth286]

As per dieselman, Mercedes original brakes discs do not warp easily, they are designed for aggressive autobahn punishment and braking from very high speeds.

Our piddly speed limits in the UK will not affect ORIGINAL Merc discs.

 

[Alps]

As per dieselman, Mercedes original brakes discs do not warp easily, they are designed for aggressive autobahn punishment and braking from very high speeds.

Our piddly speed limits in the UK will not affect ORIGINAL Merc discs.

just to add, mine were Original Mercedes discs (and pads), and they DID warp.

 

[Uberwagon]

As per dieselman, Mercedes original brakes discs do not warp easily, they are designed for aggressive autobahn punishment and braking from very high speeds.

Our piddly speed limits in the UK will not affect ORIGINAL Merc discs.

When people think there disks have warped most of the time I bet it's pad transfer.

I had this while in europe after a long run to Monaco chasing what turned out to be a police bike. Lots of brake judder after I got them really hot, then gentle driving it carried on, a few hard stops later and all was fine again, the hard stops were VERY hard though, 200kmh to 20 odd as hard as I could.

Dave!

 

[Dieselman]

yep, my indi skimmed the pads, and brushed off all the loose rust , even done a trackday with them! , still the same, changed them and hey presto, all fixed!

gave me a reason to change to greenstuff pads at the same time too!

A heavy session like a trackday will usually exaccerbate the problem as it causes more uneven deposition of friction material.

I had exactly this problem and it was getting worse, so after performing a brake warmup test I removed the disks and cleaned them with a sharpening stone.
Probelm gone, permenantly.

 

[Will]

Could be loose wheel bearings maybe as well? Just a thought.

Will

 

[Leemc2008]

New discs on order.. Could be wheel bearing this went on Impreza WRX and the garage couldnt figure it out changing my brake fluid, discs etc.. until I advised wheel bearing, that was more of a brake fade when braking and causing the brakes to have no feel..

 

[Leemc2008]

Didnt put any update to this, well.. I changed the discs and pads and the vibration is still there! Driving me crazy now..

Its only when under braking...

 

[stevesey]

Did you clean the mating surfaces thoroughly when swapping the disks (and check the runout)

 

[Leemc2008]

surfaces thoroughly cleaned, and discs run true..

 

[grober]

Seized caliper? Worn front suspension ball joints? broken front springs. Warped rear discs? Worn engine mounts. bad rear subframe mounts. Dodgy ABS system? Could be any of these. Does the abs light come on when you switch on the ignition and then go out? People have been known to remove them to hide ABS problems!

 

[Leemc2008]

The brakes dont stick on at all.. and the car doesnt pull to any side when I brake.. I dont have any vibration at all when driving, regardless of speed.. 10mph or 70mph nothing at all..

The ABS light comes on and then goes out just as it should..

Only when I'm braking, the rear brakes havent been checked.. so will check them next, failing that will have to drop it into the garage.

 

[Birdman]

Normally, when the rear discs are patched (forget warping as it is rare) the vibration transmits mainly through the car frame & seat. When the problem is at the front you feel it partly in a vibration of the steering wheel but not through the seat. In both cases the brake pedal pulsates slightly.

I wonder whether you have patching on the rear discs.