Help--Brake Problem on 16v

[jasondew]

recently i installed some new drilled rotors, new pads, braided SS brake lines, and bled the whole system with high temp brake fluid. now i have a problem. after the break-in period i was testing the brakes and managed to lock up the passenger front wheel at high speed causing a flat spot on the tire. the "ANTILOCK" light came on which means that there was a fault in the ABS and the ABS shut off subsequently. also, at the end of a brake cycle (under 5mph) i feel the pedal pulsing like the ABS is activating, somewhat roughly. some times the "ANTILOCK" light comes on and sometimes it doesn't. i'm not going fast enough for the ABS to be necessary but it feels like it's coming on. also, after the light comes and and ABS has been shut off, the pulsing in the pedal goes away completely. what would cause these two problems? did i get my wheel speed sensors dirty during the brake job? do i need new wheel speed sensors? i took it to my mechanic who bled the brakes again for good measure and the problem persists. he said he can't find the diagnostics plug to test the ABS. is there a hookup for a diagnostics computer? any help would be appreciated.

thanks

[jasondew]

i removed the wheel speed sensors and cleaned off all the metal shavings and dust that was all over the magnet. after replacing the sensors the pulsing feel of the pedal is gone but now the ANTILOCK light comes on randomly when braking. does anyone know what's going on? do i need to replace the wheel speed sensors?

thanks

[meek]

I'm going through posts and this is exactly what mine does---

at the end of a brake cycle (under 5mph) i feel the pedal pulsing like the ABS is activating, somewhat roughly.

So cleaning the sensors cured it?

Thanks.

[jasondew]

it made it better for a while but didn't cure it. i think i have a short in a sensor wire or a damaged sensor. my ANTILOCK light flickers when i turn left and goes on and off when i hit bumps. sounds like a short to me. anyway, because this is a fair weather only car i prefer no ABS actually so i just unhooked my wheelspeed sensors so the ABS shuts off immediately after i start the car. it's a cheaper fix than buying two new sensors and gives a better brake feel when braking at or near the traction limit of my tires.

[mbdoc]

Very common on cars before 1990 as the sensor(front) wires break internally & then cause this intermittant problem with ABS "thump". Test & then replace the defective sensors.

I had problems very similar to yours, and it was indeed the broken sensor/wire for the ABS. I'm sure there is a way to check them (resistance) but i don't have the benz manual, cd or otherwise. I highly reccomend doing the job yourself, its a cinch.


Dan

[jasondew]

MB Doc,

how should i test the sensors? my wife drives the car also and i would like her to have ABS so i think i will fix it afterall.

thanks