I recently bought an '86 300E with 182K. Nice car with a 5 spd, which I had been looking for. It had an obvious problem with the ABS engaging at low speeds and with the Antilock light both flickering and staying on.

I replaced the front sensors last weekend and fixed the great bulk of the problem. I am now getting a very occasional spurious ABS engagement but the warning light is still flickering and sometimes staying on.

Voltage appears to be fine.

I have convinced myself that this has to be the rear sensor both shutting down entirely and sending bad speed readings and that it is a reasonable course of action to replace it. I am trying to avoid the $75 to have it checked by the dealer.

Thoughts?

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Chuck Taylor
Falls Church VA

Have you checked the voltage output of the sensors. Attach a voltmeter and turn the wheels. I had the same problem when I changed the front sensors, they needed a (gentle) tap with a hammer. If you just tighten the screw the will not go deep enough.

Make sure you have a good overvoltage relay. Also I have seen where a severe brake squeak will cause this.

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Benzmac:
Donnie Drummonds
1992 500E (very soon I hope :)
1981 280GE SWB
ASE CERTIFIED MASTER AUTO TECHNICIAN
SERVICE MANAGER FOR 14 BAY FACILITY
MERCEDES SPECIALIST 8 YRS
PARTNER IN MERCEDESSHOP.COM

Benzmac -

I still have a sometimes flickering sometimes solid ABS light. I have three new sensors, all of which produce voltage when the wheels are turned. I have gently tapped on and retorqued the sensors to 16 ft lbs.

You said "make sure you have a good overvoltage relay." Is there a reasonably uncomplicated way to check this, or should I just call Lee and order a new one? The wiring to the ABS control unit looks rather forbidding.

I was able to check the fuse in the OVR and it is OK.

Thanks. BTW - I bought the rear sensor from you guys.

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Chuck Taylor
Falls Church VA

I just put in a new ABS Wheel sensor after replacing a ball joint.

The ABS system activated at very slow speeds, but otherwise seemed normal. The problem was that the ABS wheel sensor was not pushed in all the way. I could see a very small gap between the plastic part of the sensor and the spindle. Some gentle taps with a hammer and re-tightening of the alllen bolt fixed the problem.