2000 A4 2.8 Quattro. This is my first Audi, I bought it in March at the auction for $5000.00. I love it. I had my mechanic check it out when I first bought it and he said that the car had new brake pads but whoever replaced them put in pads without the sensors. I have not yet replaced the sensors and the brakes make a loud grinding noise when coming to a slow stop as in parking.

Just the last couple of weeks there is a loud beep and then the ABS light comes on and the brake light starts to flash. At first it would flash a couple of times and go out and it was only once in a while, now it seems to happen with every trip and the the ABS light stays solid on and the brake light flashes almost the entire time I am in the car.

Also, three times now, on sporadic occasions, I have stepped on the brake peddle and it had made a clunking noise, even my girlfriend in the passenger seat heard it, and it feels like the pedal is bumping under my foot when it does that.

Are all these incidents related, what do I look at first? What could it be? Is the car safe to drive.

 

clunking like the abs is going off? it should be a steady vibration that can come or go, depending on how long the abs stays on for. the sensors on the brake pads are just so that the car knows when the brake pads need to be changed. if the clunking noise is a steady vibration (that can be felt in the peddle), then it could be an abs sensor. especially if the abs light is going on. i would bring it to the shop and have them look at it at the next oil change. if your abs is just going on once in a while, its not life threatening, but i would definitely be careful because you might not be able to stop as short as you would like.

 

Abs sensor or abs module angry with you . Really have them inspect the brakes all over again.

 

Could be the sensor ring... they get corroded and cause funky readings making the ABS/Traction Control engage.

 

"Clunking like the abs is going off?" I have no idea what that is. It clunks like I just dropped a wrench on the floor only with less ringing and the peddle doesn't vibrate(as in a vibrator?) it is as if I stepped on it and it rolled off a rock or something. What is ABS anyway, I don't think I've ever owned a car with ABS. I'm pretty mechanical, I can fix a few things myself...but I know Nissans and old heavy metal......Audis, no clue.....but I'll tell you after driving this car I don't know how I'll ever drive anything but an Audi after this ABS or not. Any help or opinions are greatly appreciated.

 

ABS = Antilock Braking System (or Antiblokiersystem)

These systems date back to the 1920s and 1930s. Modern ABS had been installed in a large majority of production cars since 1978.

I hate to sound like a dick, but if you don't know what ABS is, you are not qualified to work on the brakes on your Audi and should leave it to a trained professional or take an ASE course before working on them, for your own safety.

 

Actually its all the same.. just different nomenclature for certain parts, but they all are and work the same.

 

Thank you although I am not planning on working on it myself, I need to have a clue when I go the mechanic. Las Vegas tends to be a city of hustlers and customer service is almost non existent here. I can't afford to get ripped off so I'd like to have a good idea of what the problem is, maybe its something common to Audis, I don't know it's my first Audi so I am in unfamiliar territory my as my last three cars were Nissans. Then I got a better shot of not being talked into calipers and a master cylinder, or a sensor only to find out my problem is because my rotors weren't cut when the pads were changed.

I know what ABS stands for I just don't quite understand their function aside from the obvious...meaning how they work not what they do. Maybe I should have started in baby steps with you guys as in:

If the sensors are missing from the pads will that make the ABS sensor go off?

Are they the same thing the brake pad sensors and the ABS sensor?

If the brakes are grinding is that because the pads are bad already, because the rotors are bad or because the sensors are missing? A month ago the mechanic told me they were new pads and the grinding was because the sensors are missing.

Is it possible that if whoever owned the car before me changed the pads but not the rotors, the rotors are cutting up the pads causing them to stick which in turn is causing the clunking noise in my brake pedal or is that something that would be more transmission related?

 

No.. you just dont get a 'pads worn, change them soon' light. You get the familiar 'squeal warning' instead.

No. The ABS sensor looks at a toothed wheel or 'ring' to see if your wheel is turning or not. If not, it releses pressure untill it does. Same type of sensor as your crank sensor (called 'hall effect'). Look for a connector on the wheel hub/spindle itself.

He's wrong...

Entirely.. have the rotors looked at.

Highly doubtful. Most likely, something is wrong wih the ABS, since the light is on, and it is engaging prematurely. It will sound pretty loud becuase the Quattro is also trying to compensate. Have someone look specifically at your sensors and sensor rings (the toothed wheel). These rings can get crudded up or rusty and throw the ABS off.

Highly doubtful.



I remeber the first time I had my ABS and Quattro (traction control) kick in.. the whole car kinda shuddered, the pedal jumped under my foot, I swear I heard a rear tire try to go backwards, and I stopped - on ice - in like 10 feet... I was like 'GO QUATTRO!"

I know the tires didnt actually reverse, but I was still impressed. All the other cars slid through the intersection... I stopped at the line

 

More..

http://auto.howstuffworks.com/auto-p...lock-brake.htm

http://autorepair.about.com/od/glossary/a/def_ABS.htm