Funny thing happened this morning, while applying the breaks, the pedal was very smusshy(techincal term). No real pressure
and it went right to the floor. The car will barely stop.

Am I correct in assuming the master cylinder or could it be something else. The fluid level was correct, no leakes.

The break pads are fine, just all of a sudden no pedal.

Any ideas?


Its a 96 A6 avant 2.8.


Thanks

 

It sounds like a leak somewhere in your hydraulic system but I wouldn't assume it to be one thing over another at this point. Check your master cylinder, brake lines, and calipers for any noticeable defects or leaks before you just start throwing money at parts that it could be.

 

sounds like/could be moisture in teh line. cheapest diagnostic is to flush and refill teh brake fluid. Nothing else fite teh symptoms. Everything else that would cause teh pedal to floorboard involve leaks, either at teh caliper, at one of teh connectors, or at the master cyl. Any/all of those leave SOME sort of obvious evidence. i.e. a puddle, SOMEWHERE. moisture/water in the line won't neccessairly show up, anywhere, but will give a "smusshy" pedal and reduce your braking to nil, or nearly so. a DIY flush and refill'll run you, what, $20, maybe $30, tops, including teh cost of gas to the parts store for some replacement fluid...

 

good lookin out AWD. how could mosture get in, condensation? that is prob the only fluid i havent flushed.

whats the process for a flush? bleed each wheel until new fluid comes through? ive blead brakes b4, but never a complete fluid replace.

is it reg dot 3/4 fluid or a 'special'?

thx.

 

Yep, drain teh resovuoir, replace with new/clean fluid, starting from the wheel farthest away, bleed until clean fluid comes through. Repeat teh bleed at each successively closer caliper.

I do not believe there is any special fluid required, but you might wanna double check that. I'm about to flush and replace MY fluid, soon, too, but I'm upgrading to a dot5 fluid (higher boiling point, less able to absorb water), so I dint bother researching Audi's brake fluid specs...

Speaking of which, yes, condensation can, over time accumulate water in your brake fluid. Dot 3/4 fluid has a certain amount of an ability to absorb this condensation without adversely affecting any of the components or teh overall performance of your system. Beyond that point the water begins to "boil" once it's heated by the surrounding brake fluid. (you'd be amazed at how much heat is generated by applying your brakes) As it boils it creats air bubbles. While fluid is not compressible, AIR, on teh other hand, IS compressible. Hence the smusshy-ness. You might get one, two stops, at best, then... well, you know.

 

So it seems I have a break fluid swap to do. Not too bad considering a master cycl is prob a much more $$$$ job.

I will check with the auto parts store on the fluid type. The higher the DOT rating the better, so if they have 4 ill get it.

Thx again, AWD.

 

And the plot thickens. Turns out it is not the fluid but the rear rubber break line has dry rotted or something so fluid squirts out all over the underside of the car.
The flex line that goes from the main hard line into the caliper


I know this because my cousin who was gonna help me bleed the system got a DOT 3 shower while checking out the driver rear wheel, well he asked me to pump the pedal and he got it. so i had to order the line $25 each. I ordered two so both rears will be new.

cant finish the job because it will be dark b4 the job gets done and i must see BIG BLUE STOMP T.O. and the 'Boys tonight.

 

you know, for about a $100.00 you cudda have stainless-steel at all 4 corners. I gotta go eat, right now, but I'll track down the website I found them at when I was looking for rear pads for my car. Or, you could always check ebay... With S/S you never hafta worry about dry-rot ever again