[quattromike]

As title I have an 1991 audi 80 quattro and the abs is not working right it started of just one wheel not braking but now all of them are up to it and I have to switch the ABS of before the car will stard braking. my question is is it safe enough to just disconnect the ABS altogether an run without any driver aids .
also if I do disconnect the abs will it still be ok for the MOT, if it has it as standard does it need to work at mot time?

cheers Mike.

 

[16V]

yes they check the ABS at MOT time -if its fitted it must work!!--- your problem has me baffled other than check the wiring to the sensors to make sure your not getting a faulty lamp come on i havent got any suggestions-but then you say that one wheel stopped braking then they all did then brakes work if you switch the system off?? do you mean the brakes stopped working or just the abs system???-i'm baffled mate

 

[quattromike]

Hi what I mean is when I start the car up the abs light comes on for a few seconds then goes out, and when I drive off after about 50 to 100 yards the light comes on again to say there is a problem and the abs has been deactivated, If I push the brake pedal before the light comes on to deactivate the abs the pedal vibrates as if the wheels were locked up and the abs is working to release the locked wheels, but because they are not locked up and it's releasing the brakes i end up not slowing down at all until the light comes on then it's all sorted and the brakes work and abs is not activated. so what I'm thinking is that at least two or more of the wheel speed sensors is not working properly and need replacing, or the problem lies deeper in the abs control box.

Mike

 

[16V]

would it be a case of dirty sensors - i believe you can remove them and clean the sensor heads--- ive never had this problem so i would like to know what is causing it-- anything you can check yourself may be save you a few quid before you take the car to audi to get the abs system checked- maybe pressure in the abs system is low???but thats a just a stab in the dark mate


dave

 

[quattromike]

Ok I'm going to buy some wheel speed sensors off ebay and try swaping them about to see if it makes a difference. If that fails I think I could get my hands on a second hand abs control unit that I could try too. so it's a case of just watch this space :thumbsup:

 

[quattromike]

Hi just to update I've changed the two sensors on the two back hubs, but what a nightmare it was , they were absolutly solid in the hub ended up drilling and heating and chizeling then drilling again and picking the bits out!
It has helped the problem but i still need to do the front hubs now so I'm not looking forward to that.

Mike

 

[quattromike]

Ok I've changed all the sensors and cleaned all the toothed parts on the drive shafts where the sensors run but still cant get the abs to work . I'm running out of ideas quick. what do I do now? :angry: :angry: :crying: uzzled:

 

[AudiRon]

You might try cleaning the probes on each of the wheels. They are easy to remove simply by prying up with a screwdriver or something with a flat end. Wip them with a cloth and simple press them back in. Try that. If that fails you may need a ABS computer.

 

[AudiRon]

Remove and clean each probe in all wheels. That should fix it. If not, you may need a ABS computer located under the back seat.

 

[quattromike]

Ok I've had all the drive shafts out again and some of the reluctor rings look a bit dodge so I've ordered new ones, I'll keep you posted on my progress. might be a few weeks though coz I'm pretty busy at work just now :crying:

Mike

 

[grobbarg]

Yeah, the rings can crack and split giving false signals...

 

[quattromike]

yipee :clap: fitted the new CVJs to the front and it's a result sorted it right out. Still failed the mot though, :huh: The exhaust was rubbing on the rear drive shaft, and the front lower wishbone bushes so no big deal.
Cheers every one for their input to my problem :beer:

Mike