Brake problem?

I have a 98 Ram1500 4X4. The brakes are acting a little wierd. There are no fluid leaks and the master is at the full mark and always has been. There are lots of pads and shoes left. Most of the time I have a nice high brake pedal. Every once in a while the pedal will go almost to the floor before any brakes start to take effect. Anybody got any idea what might be causing this?

Jack
Author: admin