Hi Guys,
I wonder if you can help me with advice about a brake problem I have with my K reg Audi 80 2L 16V Sport.
I'm not sure whether it came on gradually, but as I sat at the traffic lights recently, I noticed that if I pressed the brake pedal more than once, the brake warning light came on, and the pedal seemed to sink a little. The brakes seem to work normally on the move, and have since passed a garage rolling road test with flying colours, with or without the ABS selected. Even disconnecting the electrical supply to the ABS makes no difference. The symptoms are very consistant, and only appear at a standstill, with the engine idling.
Audi have not seen these symptoms before, and my local garage is mystified. Some say ABS, but it can't be that. Someone suggested a leak in the system, but there are no external leaks, and the pedal is rock solid with the engine stopped, but of course the warning light is on permenantly then. Can it be to do with the servo system? The warning light does not come on if either of two connections to a switch under the base of the master cylinder is disconnected, so this switch is part of the circuit involved, but what it is sensing, we do not know.
If you have any ideas, I would be very grateful.
Yours sincerely,
Bryan Cheer.
Plymouth, Devon.

 

If your model is equipped with a central hydraulic system that powers the steering and the brakes, then the Brake Accumulator AKA "brake bomb" might need replacing. If the hydraulic fluid level drops low enough the light might come on intermittently as well.

 

Thanks Offramp, but no, I don't have a "brake bomb", and all hydraulic levels are good. Yours, Bryan. PS. How are you getting on with the odometer?

 

Offramp,
I think I may owe you an apology! I have just visited the sjmtechniks site you mentioned to Audibaby, and they describe similar symptoms to my problem, and suggest, as you did, that it might be the "brake bomb", and give a run-down on how to check whether it is working. Well, it seems if I have one, it ain't doing much, so I'm going to search for it tomorrow morning, when I just happen to have the time.
I have separate reservoirs for brake and steering fluid, one is mineral, the other vegetable, I think, so surely it can't be a centralised system? If I don't find a "brake bomb", I'll be checking that servo system thoroughly. I suppose I will be better off if it is just a leaking servo system, because those bombs are expensive! The American sites I've visited are quoting 3-400 dollars. One shouldn't penny pinch with brake parts, but I may be tempted to fit a second-hand unit, if I can find one, and I will be checking to see if they can be refurbished or repaired.
So thanks again for you very prompt reply to my query. It may turn out to be the right answer. At the very least, the forum has helped me widen my knowledge about the brakes on my vehicle. I had no idea that accumulators were used in cars' braking systems, although I have met them elsewhere.
Many thanks,
Bryan.

 

Update on the brakes puzzle. Offramp was absolutely right. Hydraulics accumulator not working, so replaced it with serviceable used item, and all is good. Thanks Offramp. Cheers! PS. German/Swedish price for new item, £350 inc; used part from friendly scrapyard, £40. No contest. BC.