My brakes are not holding pressure

[seanrg1116]

I have a 93 civic Si and my brakes are not holding pressure. I will be sitting on a hill with my foot on the brake and the pedal will just get softer and softer until i start to roll.

i have changed the Master cylinder and bled the lines (2x) and i am not sure what else to try. Could the proportioning valve be bad? or the brake booster?

Reps will be given for helpful info

thanks

[JITB]

brake booster vaccum hose? could have a hole in it.

[seanrg1116]

but wouldnt that cause an irratic idle?

[JITB]

but wouldnt that cause an irratic idle?


well yea...

You can take the brake booster out, and test it yourself... i wouldnt think its air in the system, because its holding the pressure and loosing the pressure,

[jtaylor48]

on my 93 the I had the same issue and replaced the master cylinder as well. It didn't solve the problem because the s***heads @ the autoparts store gave me a refurbished unreliable piece of crap. The third one ended up working though. just a pain doing all of that bench bleeding and then bleeding the whole system again.

[Scotsman]

i also would go with the master cyl.

[Barefoot]

smalls thats your master cylinder. dont know if u got a bad part or what the deal is.

[seanrg1116]

what about the valve that is in the middle of the vacuum line that goes from the intake manifold to the brake booster

[ronin]

I was thinking it might be the master cylinder too.. i am in the same spot, i replaced mine on a 95 civic and found i still have the same problem... now i think it's the remanufactured part, i think they just replace the seals( not positive) anyway when i took it off i noticed some fluid in the area against the booster( i saw paint damage) so i'm sure it leaked into the booster area. ?????? I pretty tired of pumping the brakes to bleed them for like 900 times now.

[BB1_Luda]

I got a 93 prelude.

few years a few I had the same problem. I had to pull the ebrake when I came to a stop.
I replaced the master cylinder and it solved the problem.

[mitch lab]

brake booster