Re: Brakes; low pressure before starting

[phamh@dt.wdc.com (Hien Pham)]

> From asbury@northpole.med.uvm.edu Wed Apr 21 21:03:06 1993
> Subject: Brakes; low pressure before starting
> To: quattro@aries.East.Sun.COM (quattro@aries.east.sun.com)
> X-Mailer: ELM [version 2.3 PL11]
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> 
> To anyone interested:
> 
> I have a 1984 Audi 5000s, 4 door, fuel injected sedan just recently bought.
> There seems to be a problem with brake pressure when the car is off.  In
> the morning, the brakes go to the floor and hit a stop (I assume it is a
> stop in the master cylinder).  After starting the car and lightly pumping
> the brakes for about 2 minutes, full pressure returns.  The brake pressure
> is fine while driving or when the car stays on.  
> 
> Is this normal brake function for this car?
> If not, can the pressure accumulator be the problem?  Is there an easy way
> to check for leaks, which could possibly lead to lose of pressure over a
> long period?
> Can the master cylinder be the problem, but still allow for normal brake
> operation while driving?
> Could the problem be air in the brake system? 
> If anyone has any ideas or comments about a solution, please let me know.
> Thanks
> Jamie
> 


I read this in the old archive an saw no follow-up response. Well, I have 
some problems with the brakes before in my '85 5000 T , which may be related
to this. When I stepped on the brake pedal at a normal speed, things worked as 
normal. But if I stepped hard on it to make a sudden stop, the pedal seemed
to be locked at first, then with the same foot pressure on it, it loosely moved
toward the floor. Of course, the car moved right along without any deceleration.
Every time this happened, I had to take my foot off and to bring the pedal 
back up, then stepped down again, keep pumpimg it a few times to achieve braking.

After I have my pads replaced and the system bled, things become normal. Jamie,
if you haven't done anything to it, please have it checked out to prevent 
potential accidents.