Brake Problem

[Sodium Duck]

My brake pedal slowly glides down. It feels firm and normal to a point, but if you keep your foot on it, it slowly keeps going down. It doesn't hit the floor, but it's dang close.

Replaced master cylinder. (Also had the front axle apart recently, so I did new pads and rotors and bushings for the front). Bled all 4 brakes. Checked rear drums and found they were loose. Adjusted them up somewhat snug to the drum. Still does the same thing.

When I push the brake pedal I can hear a whooshing air noise, but the pedal catches almost instantly and I can not hear a vacuum leak. Also, I feel like I have to pump the pedal once or twice to get the brakes up high. Otherwise the brake pedal is really low.

Do I just have air in my lines or something? The pedal doesn't feel spongy...   

[zieg85]

Sounds like there is still some air in it by what you describe.  You also could have a bad replacement master cylinder... Been there....

[mattgood]

I would first bleed the brakes again to make sure no air is in the system. Also a sinking pedal could mean you have a leak, so check your calipers, wheel cylinders, lines and bleeder screws. I agree that it could also be a faulty master, although I have yet to see that.  Hope you get it figured out.

[sbx22]

Try bench bleeding if you have messed with the master brake cylinder. Matter of fact, I just did this to mine and it works wonders now. And it's easy enough, it's worth a try.