Help: Brakes Lock Up/Mushy Pedal - PeachParts Mercedes-Benz Forum

MBDad777 · #1 02-26-2003, 11:37 PM

I tested my '99 C280's brakes for a "panic stop" to see if the ABS was working. The brake pedal pulsated like it should, but one or more of the wheels locked up with a loud tire screech.

Also, the pedal feels a little mushy like there's air in one of the lines. Could the two be related or what's going on? The tires shouldn't lock up like that.

Comments? Thanks....Dan

cerbomark · #2 02-27-2003, 09:57 AM

Try with a simple brake fluid change first. This might give you a harder feeling pedal by removing air or moisture in the lines. I m not sure but I think it may be normal for a wheel to lock up enough to skid with ABS under certain conditions.

MBDad777 · #3 02-27-2003, 06:19 PM

Thanks, Mark. Can you buy ATE brake fluid at Wal-Mart? If not, where?

MBDad777 · #4 03-04-2003, 11:18 AM

Does anybody else have some input?

sbourg · #5 03-04-2003, 12:03 PM

If you are pushing hard on the brakes, the air in the lines will be compressed and heat up. Since ABS will alter line pressure to prevent lockup, it is reasonable it may not be able to function properly if the brake fluid has air (or contamination). Instead of a sharp pressure variation, it would be 'mushy'. Once a wheel loses traction, it will take a sharp brake pressure drop to get it rolling again.

Steve