The problem I'm having is when I step on the brake pedal, it's hard to push. But after applying more pressure, the brake pedal release then back to normal. Then upon releasing the pedal, the symptoms comes back.
What could be the problem? My truck is a 2004 Chevy Silverado 2500HD 6.0L 4WD.

 

Welcome to the forum. if you haven't already then you need to post your information in the Silverado section of the forum for more views.