The brake pedal on the Corvette has lost all sense of firmness. It does "firm up" if I pump it once or twice, but it doesn't seem to hold that for very long. I'm suspecting master cylinder (if I step on the brake, it doesn't hold pressure for very long). Other thoughts?
The pads are new, and it is running SuperBlue fluid that is less than a year old (of course, it has had some episodes of brake overheating on the track, so I wouldn't rule the fluid out).
Rpn
I'll bet you master cylinder.
Besides master cylinder you should check for:
1: air in system
2: hose/line leaking/expanding
3: caliper leaking
bleed the brakes fully first then reassess.
john brown has a good idea.
I know my brakes are mushy in the civic, due to fluid that is more water than dot3. It has the color of burnt molasses.
Definitely check for a leak. I had these symptoms in my truck a few years back. It turned out that one of the brake lines ruptured and was leaking.
If you even think you've had any over heating of the brakes I'd recommend a complete flushing of the brake fluid system. I recommend flushing the fluid every three months if your doing any kind to track events. While your down there look for signs of leaking. Once you've got fresh fluid in it and feel sure there are no leaks - if the problem remains - then start looking at the master. I usually start trouble shooting a problem like this with the easiest and cheapest fixes first then move on to the larger, more expensive parts.
I bleed my brakes before every track event. That way it keeps fresh fluid in the system.
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