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DoctorD15 · 03-02-2007, 09:05 PM

I have 1987 Audi 5000cs Turbo Quattro and had pretty much the same problem. This has happened to me twice since i've owned the car (which is less than a year). What would happen is the same as yours. My steering wheel would start to shake and get worse and worse the more i went, until it would shake eratically. I was almost to my destination the time this occured. I would arrive to my destination and had shut my car off. I then did what i had to do (which took about 15 minutes) got back to my car. Turned it on and right as i would try to use the brake, it would go straight to the floor. NO BRAKES. I could pump the brakes and they would work a little more each time it was pumped. I was in a development at the time, so i drove it around slowly. The brakes began to slowly come back and they would work fine the rest of the way home.

I checked for brake fluid leaks....none. My theory and other people's theories ranged. What I beleive is the culprit is the brake master cylinder. Note though that this problem would only occur when I traveled long distances.

My theory....
As I began the long destination, after a while my caliper began to hang up (could be the culprit to the shaking) which in turn caused the brake fluid to heat up. The brake fluid would eventually heat up so bad that it would cause the brake master cylinder to start malfuntioning, becuase i am told that these audi master cylinders start malfuntionaly as they get old and are exposed to multiple years of heat.

Another theory was that there was some contamination in the brake master cylinder and it would get stuck in the seal at some point and cuase these problems.

The second theory though just doesn't match every sympton.

I have yet to figure out the culprit to this problem, but it has not occured in months. It is now winter, so im not sure if that has anything to do with it.

One thing I was told to do, was when the shaking and whatnot started to occur, pull over, pop the hood, and pour a bottle of cold water on the brake master cylinder. If the master cylinder was malfuntioning due to heat then this should free up the master cylinder and cure the problem temporary or until it heated up again.

I'm not sure if you've figured out your problem, or what you've replaced, and if your replacments seemed to help anything, but i would like to know, so if you could post an update to your problem that would be great. PM me if you want to talk more in depth, because i would like to come to a conclusion to this bizare problem.

Also on another forum page i came across this thread....

Fourtitude Forums: 1987 5000 brake problem

03-02-2007, 09:05 PM	#10 (permalink)
DoctorD15 Newbie Join Date: Oct 2006 Posts: 14 Gallery: (0)	I have the same problem I have 1987 Audi 5000cs Turbo Quattro and had pretty much the same problem. This has happened to me twice since i've owned the car (which is less than a year). What would happen is the same as yours. My steering wheel would start to shake and get worse and worse the more i went, until it would shake eratically. I was almost to my destination the time this occured. I would arrive to my destination and had shut my car off. I then did what i had to do (which took about 15 minutes) got back to my car. Turned it on and right as i would try to use the brake, it would go straight to the floor. NO BRAKES. I could pump the brakes and they would work a little more each time it was pumped. I was in a development at the time, so i drove it around slowly. The brakes began to slowly come back and they would work fine the rest of the way home. I checked for brake fluid leaks....none. My theory and other people's theories ranged. What I beleive is the culprit is the brake master cylinder. Note though that this problem would only occur when I traveled long distances. My theory.... As I began the long destination, after a while my caliper began to hang up (could be the culprit to the shaking) which in turn caused the brake fluid to heat up. The brake fluid would eventually heat up so bad that it would cause the brake master cylinder to start malfuntioning, becuase i am told that these audi master cylinders start malfuntionaly as they get old and are exposed to multiple years of heat. Another theory was that there was some contamination in the brake master cylinder and it would get stuck in the seal at some point and cuase these problems. The second theory though just doesn't match every sympton. I have yet to figure out the culprit to this problem, but it has not occured in months. It is now winter, so im not sure if that has anything to do with it. One thing I was told to do, was when the shaking and whatnot started to occur, pull over, pop the hood, and pour a bottle of cold water on the brake master cylinder. If the master cylinder was malfuntioning due to heat then this should free up the master cylinder and cure the problem temporary or until it heated up again. I'm not sure if you've figured out your problem, or what you've replaced, and if your replacments seemed to help anything, but i would like to know, so if you could post an update to your problem that would be great. PM me if you want to talk more in depth, because i would like to come to a conclusion to this bizare problem. Also on another forum page i came across this thread.... Fourtitude Forums: 1987 5000 brake problem Last edited by DoctorD15 : 03-02-2007 at 09:12 PM.