Hello all, I have a 99' A6 2.8 with some brake problems. The pedal will drop to the floor if you hold steady pressure on it and my brake light flashes steady, All the pads and rotors are good and I just replaced the master cylinder and blead the entire system and no change at all. Could this be a bad ABS pump? Should the pump make any sounds? (no noise comes from the abs pump now) or could this be a sensor somewhere? Any help would be great...
Anybody around the South Hills area of Pittsburgh, PA with a Vag-com willing to scan my car? I'll bring ya a case of beer for your time (or cash if you prefer)
Thanks,
Jackson

 

Sounds like a leak in the brake booster or vac line to it.

 

Bad ABS would not have the symptons you describe...

Air in line or leak are the usual causes. Check the fluid level then bleed the system to get all the air out. Crawl under the car and look for a leak. You won't see anything on VAG Com

 

i got a question whats the fastest way to find a leak in the vacumm line? just spray the motor with water?

 

That is what I thought but this issue happened over the corse of a day and just kept getting worse. The symtoms sugested a bad master witch I have changes many times on different cars over my life but no change after the new master and full system bleeding. There are no leaks at all in this system. I have driven the car all week long locally around my house and there is no change in brake fluid level or leaks anywhere. I am at a loss here and this just doesn't make sence. Could this be a booster problem or a vac line somwhere? The brakes get rock hard when the car is off and loose all pressure when the car is started, so the booster is working just seems to be working too good... and other ideas?
Thanks

 

No leaks, no fluid loss means either vac leak, or air as stated by NH_USA

 

Don't bother testing the vac line just replace it. They are the one (and only ) part that is so cheap it's not worth checking. If you want to though I would remove it pressurize it and spray it with soapy water if it bubbles it's done.