dantan1

Hi all,

I am loving my new C400 but I have had this since a week after I got the car 1.5 months ago.

Whenever I apply light pressure or no pressure (just keep the foot on brake pedal) and let the car free roll, I can feel a grittiness grinding feel on the brake pedal. It feels like the rotors and brake pad aren't smooth and grinding on each other. I only get a slight squeal but it is not as loud as others on this forum. I have had several cars over the years, German, Japanese, and Korean cars and none of them has brakes that I can feel any grittiness. There is no pulsating, warped rotor feel.

Is this characteristic or anyone had a dealer rectify this issue for them? I brought it into 2 different corporate dealers in Vancouver, BC area and both had foreman test drive it with me and they said it doesn't feel out of the ordinary for them.

This is the first time I have cross drilled rotors so I don't know if they are supposed to feel this way (and have not been able to google find an answer).

Thanks!

ManiacGT

I don't feel this issue. It could be grit between the discs and pads? perhaps have a look at the discs (rotors) for any scoring? If there is scoring, have the dealer take a look. If not, then have them drive it anyhow and see what they say.

Glyn M Ruck

My CLK did this new. New pads & rotors fixed for a while. When it returned front pads were half worn. They wanted to change the whole lot again. I said don't, just change pads. It has been perfect ever since.

Try and do a proper brake bed in. Method on the Stoptech website. You have to deposit a layer of friction material evenly on the rotor.

This can also be an issue in coastal areas or areas where salt is laid on roads. Corrosion micropitting of the rotor occurs & the only fix is replacement.

This only occurs during extremely light braking when the pads contact the rotor. Any harder and it goes away.

Good luck!

dantan1

Thanks for the notes Glyk and Maniac, I tried a half bed in before as recommended on one article for OEMs (was a weekend and too many cyclists on the mountain road). But managed to do 3 slow, 3 hard. Will try the full bed in.

Will the bed in process ruin the pads? Or 10 hard stops from 60mph. Coz these are OEMs not race pads.

Glyn M Ruck

Bed in process will cure the pads ~ no harm!

dantan1

Thanks! Will try it and update if it works.

Glyn M Ruck

After the procedure you will notice some heat bluing of the rotors. Don't worry about it.

dantan1

Noted on that. Waiting for a non rainy day (tmrw) to head up the hills! Thanks

dantan1

I did one cycle (10) of the bed in and it seems just slightly "smoother". But I didn't do the second cycle as recommended by StopTech because I noticed that the blackish pad onto the rotors were not full length. Ie it seemed the outer side was not rubbing on and could be an uneven pad? Anyone has any idea if this is normal or should I bring in the car? I'll bring it to a dealership not a corporate store since maybe dealerships make money (labour) on warranty repairs? The rotor pic is attached

Glyn M Ruck

If it's still there I would at least make them fit a new set of pads.

dantan1

Thank Gyln, I might just do that. Now to find a time during work week!