My brother has as 04 1500 Z71 Sierra which has poor brakes. It has vaccum boost. Dealer says it stops. Brakes are spongy and the pedal has to be pushed almost to the floor to get it to stop on a step hill. Is there a fix or recommendation?

Without driving the truck, its hard to say, but just a piece of info, federal rules are changing every year, starting in 04, they required less of a pedal effort to stop the vehicle, basically there is more assist than previous years, giving the pedal a softer feel. From what I understand, they will be reducing that effort by some more. I can not remember the exact figures, but it was something like previous pedal effort of 120 pounds and in 04 went to 80 pounds. Dont quote me on that.

After contacting GM, my dealer called me now and wants to try and change the master cylinder....its free so, just waiting for his call....will advise when its done

See my post on spongy brakes...