Brake Failure light has been coming on. I replaced a caliper and new brakes all around. As well as the master cylinder. I bled all the calipers from furthest caliper to closest to the cylinder. Brakes feel very firm until I turn the car on. That's when I lose pressure.
If I pump several times the pedal will firm up. But I notice when I press the brake the idle in the car drops. I hear the whoosh and see air entering the master cylinder reservoir. At times the pedal will sponge to the floor. I removed the boost check valve hose and tried to blow through the intake end and no air pushed through. I blew from the check valve side and air moved through 50% with the diaphragm inside sounding rough. I removed the valve and checked the hose for any areas where air could escape. Air blew strong through the hose.
Also when I removed the check valve from the booster a lot of pressure removed. So I do believe the brake booster is making proper pressure. At this point I am really leaning towards the brake booster check valve being bad.
If I pump several times the pedal will firm up. But I notice when I press the brake the idle in the car drops. I hear the whoosh and see air entering the master cylinder reservoir. At times the pedal will sponge to the floor. I removed the boost check valve hose and tried to blow through the intake end and no air pushed through. I blew from the check valve side and air moved through 50% with the diaphragm inside sounding rough. I removed the valve and checked the hose for any areas where air could escape. Air blew strong through the hose.
Also when I removed the check valve from the booster a lot of pressure removed. So I do believe the brake booster is making proper pressure. At this point I am really leaning towards the brake booster check valve being bad.