Brake Issues - advice needed
Thread Starter
Melting Slicks
Joined: Aug 2005
Posts: 2,995
Likes: 61
From: Fort Wayne IN
Brake Issues - advice needed
Posted in C5 Tech but not much response so I'm posting here
A friend of mine has a 2001 A4 Coupe that for some unexplained reason will start dragging the brakes without any pedal input. No current or history codes came up when I checked today. He had it towed to the stealership where they said the incorrect brake fluid had been used and all of the rubber components in the system would have to be replaced?????? At a cost of $4,000 no less. When the car is driven it's ok for a few blocks then it feels like the brakes start dragging. Turned AH/TC off and no change. Funny thing the brake fluid cap rubber gasket is way oversize now - like it swollen and it won't fit because it's too large so the dealer may be on the right track. If someone put DOT 5 fluid in by mistake could that cause the master cylinder to act up? I found no leaks anywhere however and he has not changed the brake fluid recently but you never know if some helpful tech topped of the fluid with DOT5 by mistake during an oil change. I know for a fact that DOT 5 is not compatable with our brake systems.
Input/comments appreciated
Regards
A friend of mine has a 2001 A4 Coupe that for some unexplained reason will start dragging the brakes without any pedal input. No current or history codes came up when I checked today. He had it towed to the stealership where they said the incorrect brake fluid had been used and all of the rubber components in the system would have to be replaced?????? At a cost of $4,000 no less. When the car is driven it's ok for a few blocks then it feels like the brakes start dragging. Turned AH/TC off and no change. Funny thing the brake fluid cap rubber gasket is way oversize now - like it swollen and it won't fit because it's too large so the dealer may be on the right track. If someone put DOT 5 fluid in by mistake could that cause the master cylinder to act up? I found no leaks anywhere however and he has not changed the brake fluid recently but you never know if some helpful tech topped of the fluid with DOT5 by mistake during an oil change. I know for a fact that DOT 5 is not compatable with our brake systems.
Input/comments appreciated
Regards
Le Mans Master
Joined: Sep 2003
Posts: 8,847
Likes: 795
From: Longview Texas
If the rubber parts are swollen, it is a good bet that the system has been contaminated with something.
I have even known an oil change center to add transmission fluid to the brake reservoir by mistake.
If the fluid is correct, I had a problem once where the brake hoses to the calipers deteriorated from the inside and flaps of rubber on the inside wall were acting like a check valve. Same symptoms, the brakes would not release.
I have even known an oil change center to add transmission fluid to the brake reservoir by mistake.
If the fluid is correct, I had a problem once where the brake hoses to the calipers deteriorated from the inside and flaps of rubber on the inside wall were acting like a check valve. Same symptoms, the brakes would not release.
Burning Brakes
Joined: Mar 2005
Posts: 1,112
Likes: 1
From: Torrance CA
Unfortunately, I have had this happen to my 2004
. What you describe is exactly what happens when power steering fluid is placed into the brake fluid resevoir. It only takes a small amount (5% or less) to destroy all of the rubber components of the system. It cost about $4800 to fix on my car. It must be fixed too as eventually, the brakes may completely fail.
Sorry to be the bearer of bad news.
. What you describe is exactly what happens when power steering fluid is placed into the brake fluid resevoir. It only takes a small amount (5% or less) to destroy all of the rubber components of the system. It cost about $4800 to fix on my car. It must be fixed too as eventually, the brakes may completely fail.Sorry to be the bearer of bad news.
Team Owner
Joined: May 2001
Posts: 36,836
Likes: 244
From: Dear Karma, I have a list of people you missed.
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I agree with the others. Either P/S fluid or some other mineral based fluid was put in there. DOT 5 (silicone based), although not suitable for our system, takes a much longer time to show problems.
My vote is P/S fluid since it will react so quickly.
HTH,
Robert
My vote is P/S fluid since it will react so quickly.
HTH,
Robert
Tech Contributor
Joined: Oct 1999
Posts: 41,044
Likes: 9,808
From: Charlotte, NC (formerly Endicott, NY)
Bill
Team Owner
Joined: Sep 2003
Posts: 43,084
Likes: 33
From: Raleigh / Rolesville NC
Time to put the car on four jack stands. Get a few bottles of DOT4 brake fluid from the autoparts store.
Suck out the old brake fluid from the MC and put in new DOT4. then Bleed the brakes with a power bleeder. Not mini-vac, but push the brake fluid though the lines with the Power bleeder ( opens ABS - mini vac does not open the ABS).
Run a two quarts though all the lines. Put the wheels back on, take it for a drive and hit the bakes a few times. If it stops well, hit the brakes harder a few times. give a few very hard stops
Take the car back to your garage and put it back on the jack stands, take the wheels off and flush the brake system again.
Time involved, 3/4s of day. Cost about 4-5 liters of DOT 4 brake fluid and few soft drinks.
Suck out the old brake fluid from the MC and put in new DOT4. then Bleed the brakes with a power bleeder. Not mini-vac, but push the brake fluid though the lines with the Power bleeder ( opens ABS - mini vac does not open the ABS).
Run a two quarts though all the lines. Put the wheels back on, take it for a drive and hit the bakes a few times. If it stops well, hit the brakes harder a few times. give a few very hard stops
Take the car back to your garage and put it back on the jack stands, take the wheels off and flush the brake system again.
Time involved, 3/4s of day. Cost about 4-5 liters of DOT 4 brake fluid and few soft drinks.
Burning Brakes
Joined: Mar 2005
Posts: 1,112
Likes: 1
From: Torrance CA
I didn't think about it when I posted earlier, but the damage was covered by my insurance company so it didn't cost me anything to get it fixed. I had a receipt for the brake job and then less than 24 hours later started experiencing severe problems. It was covered under my comprehensive policy. The insurance company was able to recover the costs from the brake shop and hence, I even receieved back my deductable.
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