Questionable MC installed
Thread Starter
Heel & Toe
Joined: Oct 2008
Posts: 22
Likes: 0
From: Perry Michigan
Questionable MC installed
Due to lack of time etc. I had someone install a rebuilt engine in my 70 power brake coupe. They also said my MC was leaking causing spongy brakes, so I told them to put a new one on. I think the MC came from CARQUEST. Anyway, now my brake pedal is about half way to the floor (real close that I have problems with the gas pedal). Did this guy install the wrong MC?
Race Director
Joined: Jan 2000
Posts: 12,399
Likes: 247
From: San Jose CA
Air in the brake line will cause the pedal to feel soft/spongy and not return on their own. Pulling it back with your hand/foot should work though.
The premise of the hydraulic system is that the fluid is not particularly compressible. When you put your foot down, it fluid into the line which tries to go somewhere -> out towards the brake pads via the lines, calipers and ultimately pistons.
When there is air in the line, the air compresses quite easily, which means it takes up far less space than it did in the relaxed state. Ergo, the pedal falls to the floor and it's no big deal for the pedal to stay there. The hydraulic fluid with the lack of pressure input will want to return.
Last edited by Shark Racer; Jan 10, 2013 at 06:39 PM.
