jdmland

No brake pressure when the car is running, when the car is turned off the brake pedal is stiff?
no leaks anywhere
Anybody?

madcrossover

iTrader: (1)

I would say it's the Brake Master Cylinder. Have you changed brakes or opened the lines for something?

xxrjxx

sounds like power brake booster

jdmland

Car sat for 6 years, all new lines.
Fresh fluid coming out of every bleeder, no leaks
mastercylinder has been sitting on the shelf for about the same amount of years, bench blead it, no air.
Fluid stays level, pressure when the car is off but no when the car is turned on.
Don't think its the brake booster, if that was bad the brakes would be so hard to push on because there is no power assist.

1990_integra_DA9

I think its an issue w/ the valving inside the master. I have had it with other cars when you press on the brakes w/ engine off. Then turn the car on and the brake pedal goes to the floor once you push it down. Definately sounds like a master cylinder.

jdmland

Well i pulled the mastercylinder off again to bench bleed, and i noticed there was fluid between mastercylinder and booster.
Seems like the mastercylinder is leaking from the back, but when i bench blead it, there was no bubbles, leaning towards mastercylinder going bad, anbody confirm?

1990_integra_DA9

Its "normal" for a little fluid to be between the master and booster. But a lot isnt. So I would start with a new master. but thats just me

6SPD_EK

iTrader: (2)

any updates I have the same issue

Crash6066

check your vacume lines to the brake booster make sure there not clogged or attached wrong.

6SPD_EK

iTrader: (2)

My pedal is firm when the car is off (no vacuum assist) but the 1st pump with the engine running & the pedal sinks to the floor. a couple of pumps & its firm. I think I might just buy a new M/C

Crash6066

double check your calipers on my civic when ever i went over lots of bumps my calipers would lose their pressure and i would have to pump the pedal a couple of times. they never leaked but the pedal did have to be pressed a couple of times

724chris

try a new mc. i bought one brand new to find out it was bad too! changed it again and it was good, i was stumped for days..