Brake pressure problem
Thread Starter
Intermediate
Joined: Nov 2000
Posts: 49
Likes: 0
From: Warrenton, VA, USA
Brake pressure problem
I recently had the dealer put on new drilled & sloted rotors on the front of my 98 coupe. Brakes work great when stopping (vibration gone); however, when sitting at a light or some other stopped position for any length of time and holding down the brake pedal with limited pressure (as I have done for my 40 odd years of driving), the pressure bleeds down and the pedal slowly goes to the floor. If I don't increase foot pressure, the car will start to slip forward. The only way to avoid this is to put and keep heavy pressure on the brake. This stops the leaking down, but is rather aggravating and tiring. This condition only started after putting on the new rotors. What's up and what do I do to fix it?
Melting Slicks
Joined: Jul 2001
Posts: 2,188
Likes: 0
From: not speeding just flying low
Re: Brake pressure problem (GFHice)
There is definately a problem with your brake system. It should feel exactly the same as before they installed the rotors. I would take it back immediatly and have it looked at. Let us know how it turns out and what is wrong.
Team Owner
Joined: Sep 2001
Posts: 23,283
Likes: 906
From: Lake Elsinore, CA
Re: Brake pressure problem (GFHice)
Sounds like they didn't bleed all the air out of the system - that's assuming they disconnected the lines for some reason, perhaps to install new brake lines. If all they did was swap rotors without opening the hydraulics, then something else is amiss.
Thread Starter
Intermediate
Joined: Nov 2000
Posts: 49
Likes: 0
From: Warrenton, VA, USA
Re: Brake pressure problem (GFHice)
I watched the whole procedure. Nothing was disconnected or bled. Pistons were compressed to allow new rotors to be mounted. With any previous car I've had (over 40) anytime air got into the system the pedal could go to the floor unless you pumped the pedal prior to trying to stop. This is more strange to me, since initial stopping is fine and its only with moderate pressure after being stopped that the pedal goes down. I will take in in, but would appreciate any further thoughts on what might be wrong. I don't like the idea of any problem with brakes -- when you need to stop, you need to stop.
Racer
Joined: Feb 2001
Posts: 286
Likes: 0
From: Bayville NJ
Re: Brake pressure problem (GFHice)
It's not air in the lines. "It's not a boating accident. It's not Jack the Ripper. It's a great white...." (Jaws). It's a scored master cylinder or at very least, dirt in the master cylinder trapped between the piston ring and the bore. Heavy pressure deforms the piston ring and makes it seal.
