vcreddy

Hi my A4 1.8 1997 brings on abs and handbrake light while driving when the speed exceeds 90km/hr and stays on until the car is stopped and rests for few hours, if I drive at low speed even for long time it does not only when speed exceeds they come on and stay continiously (no flashing) what could be wrong when i bought the car i got the lower/ upper arms, susoension bushes changed and replaced discs on the front. All these repairs were done from a local mechanic who is a suspension specialist and the spares were purchased from non audi dealer.

Looking for some help on how to get this fixed.
Thanks in advance

twentysevenlitres

Pull, clean and reinstall the ABS speed sensors and copper cages on all four wheels. Reinstall with some WD40.
The hall effect sensors need good electrical contact and need to be very close to the ABS sensor ring to work accurately.
They are a simple push fit and quite easy to knock around or not seat properly when working in the vicinity (ie suspension work).

vcreddy

Thank you for the quick reply...Will i be able to do this myself by opening the tryes. do you have any links to videos for this repair.

twentysevenlitres

Yes, easy access behind wheels.
Do fronts first.
No guarantee this will fix your issue, but sensors seem most likely culprit, and this fix is cheap and easy...
All you need is a can of WD40 (get one with a nozzle extension tube and use it), a toothbrush, a rag and a pair of needle nosed pliers:

• Remove ABS sensor
  • located on main hub, behind brake rotor, on rear top of hub.
    Front sensors have a wire that enters a hole in the hub carrier and exits again near upper control arms.
  • Sensor simply pulls out, minor twisting is Ok. Use fingers only, no tools. Do not pull by the wire.
• Carefully remove copper cage still in hole with needle nosed pliers. It too is only a press fit in the hole
• Using WD40, toothbrush, and rag, clean the sensor, copper cage and mounting hole **
  • the rubber dust cap can be removed from the sensor to clean it if desired. Just remember to remount it afterwards.
    The condition of the rubber will probably be hard, but don't be too concerned, as it's main function is to slow entry of dust and grit into the sensor hole, and it will do that just fine provided it's in one piece.
• Remount copper cage and sensor in hole.
  • orientation of copper cage should be that two flat tabs are on top to keep its place in the hole.
  • push sensor home reasonably firmly. It is seated properly when the rubber dust cap is flush, along with the sensor wire
• Repeat for other wheels

** Do not spray any oil onto brake components. Should WD40 get sprayed onto the brakes, wash off with solvent like wax and grease remover, degreaser (doesn't dry quickly), carby cleaner, or petrol.



I did find a YouTube video .
Video is stills only with German text.
Shows location of sensor, and copper cage. Also demonstrates removal of sensor if seized in hole (I suggest seeking mechanics help if yours is seized and you're not an experienced DIYer).
Do not use the tools demonstrated unless you plan to destroy a seized sensor.