john baker - PeachParts Mercedes-Benz Forum

jba75152 · #1 10-19-2005, 06:07 AM

Please help
My 83 model 380 SEL
Yhe yellow ABS light goes out when the engine starts but comes on again once the vehisle is in motion.
The brakes have good pads and the oil is ok and the brakes work well
but the abs may not be working

mbdoc · #2 10-19-2005, 08:07 AM

The car has 3 ABS speed sensors, at least 1 of them is malfunctioning!

jba75152 · #3 10-19-2005, 04:57 PM

re 380SEL ABS light Thanks for the reply.But where are the sensors?

MikeTangas · #4 10-19-2005, 05:17 PM

1 at the rear diff, mounted to the right side of the housing, 2 up front, one each side mounted to the steering knuckle.

jba75152 · #5 10-21-2005, 06:25 AM

Thanks Mike
The sensors look fine ie no damage
I will get some help with the electrics at the unit relays etc

#6 10-21-2005, 06:40 AM

A loose wheel bearing or improper adjustment will cause this . Also you can check the sensors by tracing the wire from the wheel upwards to the inner fender and disconnect it there then hook a volt meter to the connection from the sensor ,then spin the tire as fast as you can it should give you a voltage reading of a couple of volts. No voltage then sensor is Kaput . The rear one is a little harder to do and I have only had one go bad in my time. Make certain that there are no pieces or filings attached to the sensors by removing them and wiping them off.

MikeTangas · #7 10-21-2005, 06:54 AM

You probably need to start by pulling the front sensors and cleaning the sensor ends and toothed timing gear (which is part of the rotor). Should be able to clean the gear by spraying brake cleaner through the sensor hole. What happens is the fine metal dust gets attracted to the magnetic sensor whichs blocks the signal.