I have a 1994 Chevy Blazer, and the brake pedal travel is too great before actual stopping begins. The truck has 65,000 miles, and it has new brakes on all wheels.
We're gonna have to start with the basics. First off, pull the rear drums and inspect the shoes. We want to make sure they are adjusted properly. If not, determine where the problem lies with the self adjuster hardware. Next go after the hydraulic aspects of the braking system. Common sense tells us to be sure the brake fluid reservoir is full and there are no external leaks anywhere in the system (wheel cylinders, calipers, lines, hoses or the master cylinder).
Then go ahead and bleed the brakes thoroughly at all four wheels even if there were no leaks found. If your truck is equipped with two or four wheel anti-lock brakes, normal bleeding will do the trick unless parts of the anti-lock system were removed and became air bound.
If all these areas check out OK, the process of elimination brings us down to a hydraulic leak within the master cylinder at either the primary or secondary piston. Don't attempt an overhaul. Replace it!
These steps should cover the bases unless you're dealing with an oddball problem like the pedal assembly coming apart or the brake booster falling off.