Help with Brakes

[mdnt_7]

My brake pedal is extremely hard on top, and seems not to depress no matter how hard you push on it. It's like pushing on a brick wall. Also, no matter how hard you press the brakes, the car has alot of difficulty in stopping. I changed the master cylinder, brake lines, and brake booster, and pads. I've must've bled the brakes a dozen times, removed/re-checked the master and booster to check for air/improper istallation, but the problem still exists.

Thanks!!!

[BDSL]

Brake pistons might be seized.

[mdnt_7]

Thanks, I just checked the pistons, but they're okay. I'm running out of ideas...anyone?

[csaxon]

Did you bleed the master cylinder before bleeding the brake lines? Did you adjust the brake booster push rod? Do you have ABS, 4 wheel disk, VSC?

[mdnt_7]

I did bleed the master and checked the booster pushrod before installation. The car is an AE86. 4-wheel disc, No ABS and no VSC. Thanks again.

[csaxon]

Possibly a vacuum restriction to the brake booster (e.g., clogged line, fitting, etc.). To test for this, pump your brakes, with the engine off, until there is no residual vacuum assist. Then, while pushing on the brake pedal, start the engine. The brake pedal should immediately go farther down as the vacuum assist (boost) kicks in. If, however, the pedal only slowly goes down, or doesn't go down at all, you should start looking for an obstruction in the vacuum line.