Brake Pedal

I have a 90 GMC 1500 4x4. When I push the brake pedal it seems to not really start braking until it gets more than half way down. If I push down, then let up , then push immediatly back down, it grabs right at the top. It's almost like I have to pump to stop. I have replaced the master cylinder, front pads and rotors. Bled all four wheels several times. I haven't replaced the back brakes yet, but would the back give me that much more pedal?? Any help is greatly appreciated.

90GMC44

Check your rear brakes, worn or out of adjustment rear shoes can cause a low pedal, also you could have a leaking wheel cylinder causing the problem. Not to mention that style of truck has problems with rear axle seal leaks and while you are there you can check for that problem as well.

Thanks for the info. I will see what I find out.

I have a 90 GMC 1500 4x4. When I push the brake pedal it seems to not really start braking until it gets more than half way down. If I push down, then let up , then push immediatly back down, it grabs right at the top. It's almost like I have to pump to stop. I have replaced the master cylinder, front pads and rotors. Bled all four wheels several times. I haven't replaced the back brakes yet, but would the back give me that much more pedal?? Any help is greatly appreciated.

90GMC44

It does sound like adjustment. Low but solid pedal = adjustment,
Spongy feeling pedal = need to bleed.
The rear drum brakes self adjust only when applied while backing.
So if you back up then put it into drive without applying the brakes very much, they will not be adjusting.