[kingbuzzie]

So something is happening more and more frequently with my sub. The brakes are pressurized and rock hard when I go to press them before starting up the car. It usually happens overnight. Once the car is cranked and the booster works, the pedal drops to normal pressure. Also, and I think this is ever so slight... but the brakes feel a bit spongy to me. Is there a booster check valve, would it cause this, and where is it located?

 

[ForesterCub]

How long have you had this issue? Has it coincided with a recent brake fluid change? I'm asking because a recent brake fluid change done badly can cause more problems than old brake fluid left unchanged.

From what you describe, it sounds as though you may have some air in your system. A hard pedal without the engine running is normal. Having to pump the pedal a few times to get a better response is symptomatic of air in the system. I'd start at that point and go from there.

 

[kingbuzzie]

No, no brake fluid change. It has dropped some over time, but I imagine my pads are getting close to replacement. It's common to have the brake pedal rock hard with no give what so ever with the engine off? Because this only happens to me intermittently. Other times the pedal as some give when I step on it while cranking the car.

 

[ForesterCub]

Generally, it's normal for the brake pedal to become very firm after a couple of pushes on it with the ignition off.

Maybe consider a brake service / fluid change, just to make sure everything is OK.