New problem : when I apply my brake pedal hard I get a slight hissing noise. I have been noticing that when I am driving and apply my brake normally they feel fine. But the other day I was coming up to a stop light and it changed to red and when I pressed a little extra hard on the pedal it just felt like the brakes were fading but the the pedal was normal.No matter how hard I pressed it made no difference. The truck finally stopped but barely. Would not lock up - no way.I thought at the time I heard a little hissing noise but was not sure. The front rotors and pads are brand new. I am going to check the rears and make sure they are adjusted correctly next. The pedal is at normal height and does not sink under constant pressure. I'm assuming that if I can't find anything else it's the booster. My experience with cars is that boosters doe not go bad that often but ... Does anyone have anyother ideas or has faced a similar problem with these trucks ? Thanks

 

did you bleed the brakes? if not that unplug the abs unit and drive it around and see if you still hear the hissing, if not then you will have to get the abs module reset.

 

Check the vacuum line going to the booster...it should hiss any time the engine is running if there is a leak. If thats not it, hissing when you press the brake pedal could mean a leak in the diafram in the brake booster.

 

replaced the brake booster and that fixed it. Thanks for the replies.