brake pressure "buildup"

[djtodd]

Anyone ever had a problem with pedal pressure building up overnight?

Every morning the pedal pressure is extremely high, I can barely press the pedal, and even when I do it doesn't hardly any apply pressure to the brakes. I can take it our of first and hold the brake and the car still rolls.

After cranking the car everything returns to normal.

Think maybe I've got a leak in the line somewhere? The pedal has gotten a little spongy over the last few months, air getting in somewhere maybe?

I'm planning on changing pads pretty soon so I wanted to see if anyone had any advice so maybe I could take care of the problem at the same time.

Thanks guys.

[Calvin]

.Sounds like you are losing vacuum, which is what gives you the power-assist on the pedal.

There is a large vacuum line that runs across the firewall and connects to the brake booster. IIRC, there is a check-valve about midway along that line. That valve may be shot.

[yellow_jacket]

Not an uncommon thing to happen. Nothing to really worry about unless it really bothers you or it gets worse and starts leaking vacuum while the car is running.

It would either be the check valve or the seals in the brake booster.

[drift9]

I believe its because you have power brakes and they operate off of the vacume created by the engine when its running there for if the car is not running its goin to be very stiff un till you turn the engine on.Quote "After cranking the car everything returns to normal."

[Chezedik]

would be a bad check valve or a leaky diaphragm in your booster. Start the car, without hitting the brakes put your head under the console and listen for a hiss. If you hear one then you have a booster malfunction. Hit the brakes, you should hear a hiss, if you do not, you probably have a bad check valve. Shut the car off, hit the pedal, you should hear a hiss, if you do not, you probably have a bad check valve. If you do not hear a hiss when you hit the brake in the morning, you have a failure of one of these parts. So to clarify, I just said exactly what these other three guys have said.