stackz

ok, 93 civic hatch with rear disc setup from a 91 integra. I'm using the booster/master cylinder and prop valve from the 91 integra as well. stock civic front brakes. I always had a little bit of brake fade at long stop lights but other than that no problems.

the car has sat for about 1.5years. I cranked it up today to move it so I could get another car out of the garage and because I'm going to start driving it again due to gas prices lately. anyway, when I cranked it the pedal had no feel to it. I go look inside the master cylinder reservoir and its bone dry. I'm looking at all 4 wheels as well as chasing the lines and looking for leakage at the master cylinder, etc and I cant find ANYTHING. no residue/stains on the ground where the car has sat. Its like the brake fluid just went poof.

any ideas?

DelsolVted

brake fluid does evaporate over time if air gets to it.

stackz

but even if the cap is on the reservoir?

ChristianL

If it's not leaking at the brake lines, take a peek under the dash where the brake pedal goes through the firewall to the brake master cylinder. If it's nowhere else on the car, it's probably a bad rubber diaphragm on the master cylinder, and it's leaking down the firewall onto the upper edge of your carpet.

canadaek

the clutch master can leak into the car the brake master cannot due to the brake booster that's between it and the firewall i have seen them leak into the booster before pull off the vacuum line and stick a zip tie inside and see if it gets wet

stackz

ended up being the master cylinder was leaking while the car sat. noticed paint bubbling on the underside of the brake booster while I was doing the timing belt.

popped the master cylinder off and yep, nice and wet in there, backside seal was blown. new master cylinder and my brake fade issues are gone too, go figure lol.

took me nearly 2 weeks to notice it due to the way the brake fluid had dripped down the brake booster...and then followed the gas lines along the body until it evaporated so it never actually leaked to the ground...