Ok I bought this 00 Civic EX and every once in a while the brake pedal will go to the floor like i haven't bled my brakes. It only happens every once in a blue moon. We have bled the brakes and all that just wondering if something could be going bad that needs replacing or what not.

 

Check the master cylinder for leaks.

 

The MC piston o-rings are leaking. Remove and replace.

 

never messed with the MC on brakes, where is it locted?

 

Kinda like a big round thing mounted vertically on your firewall on the driver side just below the brake fluid reservoir.

 

Its actually mounted horizantally. The big round thing you're refering to is the booster that the MC is attached to. The MC is attached to the brake booster via 2 10mm nuts I think. There are also hard lines attached to the MC itself and you'll have to remove those from the MC also.

 

thanks for the help yall, the MC normally expensive to replace?

 

You might be able to get away with spending less than 80 bucks for a remanufactured one from autozone.