Brakes: smooth low speed, shuddering at higher speeds - PeachParts Mercedes-Benz Forum

haasman · #1 09-21-2003, 12:49 PM

Any suggestions on this one?

The 300E brakes normally and smoothly a low speeds but from higher (such as highway) speeds the front end shudders.

Someone recently posted a very similiar problem with a picture but after many searches I could not find the thread.

I pulled a front wheel. The rotor has what looks like spots on it that are brown. What causes this?

Do I have an ABS sensor problem?

Haasman

themadgerman · #2 09-21-2003, 03:43 PM

Sounds to me like you have warped rotors. On one of my cars (one I rather forget I owned) started out like that. I got worse. Replaced the rotors and pads and the shuddering was gone.

Mike

carkahlua · #3 09-22-2003, 10:31 AM

I had the exact same problem when I purchase my pre-owned 93 300E. My "Mercedes" mechanic said the brake pads were just fine but the rotors needed to be replaced. Rotors were $57.00 each and he charged $80.00 to put them on. The car brakes perfectly now at all speeds.

haasman · #4 09-22-2003, 10:43 AM

I pulled the rotors, got them turned, reinstalled and all is smooth now. They were cross-drilled, by the way.

Haasman

manny · #5 09-22-2003, 12:10 PM

Quote:

Originally posted by haasman
I pulled the rotors, got them turned, reinstalled and all is smooth now. They were cross-drilled, by the way.

Haasman

The moral of the story is ?

haasman · #6 09-22-2003, 01:54 PM

-With applicaton of the brakes at low speeds normal
-Using the brakes above about 40MPH produced severe pulsing and shudder from the front
-Checked all front-end links, rods etc, all seemed tight and sound
-Discovered rotors were waved
-Took off the rotors, observed spotting all around their surfaces
-Had them turned (some places do not turn (cut) cross-drilled rotors)
-Reinstalled
-Smooooth braking above 40MPH

The moral of the story: If you have brake pulsing and shuddering above 40MPH and you are sure all of the suspension pieces are tight and correct, it is very likely it is your front rotors .....

or Life is good once again.

Haasman

manny · #7 09-22-2003, 04:54 PM

haasman

I just wanted to clarify the following:
1. Rotors can warp, cross-drilled or not.
2. Cross-drilled rotors CAN be machined.

haasman · #8 09-22-2003, 08:20 PM

manny

Yes to #1 AND #2

Haasman

400E · #9 09-22-2003, 08:51 PM

I believe MB officially does not sanction turning rotors -- they are pretty specific that they should be replaced when they fall below service thickness limits.

On the other hand, you apparently had plenty of material left but just wanted to smooth out the waves.

haasman · #10 09-22-2003, 09:05 PM

Steve

You are correct. No rotor that is below minimum thickness is safe on any car for risk for hyper-extension of the caliper pistons.

As a matter of California state law, no parts company will turn a rotor that results in an undersized thickness.

Correct once again, since the resulting thickness after turning met the minimum thickness spec, it was permissible.

The results I experienced are excellent so far.

Haasman