so i had some caliper problems on my crx so i decided to replace most of my brakes. replaced both calipers,pads,rotors,drums in the back with all new hardware,rebuilt master cylinder and brake booster. bled the brakes and have some pressure but not nearly enough. bench bled the master cylinder also. so i took the new brake booster back thinking maybe it was faulty and got my old one back..same problem. the only thing i can think of is the master cylinder if faulty. i get brake pressure but not much. i can stop but if i were to slam on my brakes it deff would stop like i should.
with the car off ill pump my brakes and get good pressure.start the car and then pedal with drop down alot. almost to the floor. also when im at a light or stop sign ill push my brake pedal and the rpms go up. and then when i release the brake pedal the rpms go back down

ive also read about adjusting the master cylinder push rod? i have little play in my brake pedal. ive tested it with my hand so i dont think that is it. unless i am reading it wrong. ive been trying to figure this out on my own for almost two weeks now and have gone though alot of money,time,and AGGERVATION. any help would greatly be appreciated

 

Sounds like a faulty master or air in the line? How did you bleed the system? I've found using a power bleeder/vacuum bleeder works best. Start at the farthest wheel and work toward the front drivers.

 

did you install the brake booster check valve in the wrong direction, when you hit the brakes the rpms go up that tells me there may be something wrong with the booster considering thats the only thing that has any thing to do with the engine and as far as the brakes how did you bleed the brakes. because old chevy guys like to pump the brakes up. the right way to bleed the brakes is fill the master cylinder with fluid and go to the pass rear wheel have the guy/gal in the car push the pedal down then you crack the bleeder the pedle will go to the floor for them they hold the pedel to the floor then you tighten the bleeder and say up then you repeat this operation till there is a good stream of clean brake fluid remeber dont get air in to the master cylinder i did this on a rsx last week it took me 45 mins just to get all the air out of the system check the fluid every time you bleed one side. if you really worried about air bleed each wheel like 10-15 time then test good luck

 

Did you replace the breaklines?

 

I'm having the same problem with my '90 CRX minus the part you said about the rpm's going up when pushing on the pedal. My brakes are horrible, it has no pressure at all. I can't figure out whats wrong with it!

 

is the master cylinder new or remanufacured because i have put 2 reman. master cylinders on both of my crx's and with in a year they rear seal was leaking on the brake booster again so if its a remanufactured unit id take it back and get a new one