I have a chevy silverado c1500 1998. My brakes are going to the floor and my calipers are locking up. They were fine before but my rotors were bad and I replaced them. I also replaced my pads when I replaced the rotors. When I tried to test the breaks they went to the floor and before I got a block away the calipers were locking up. I thought that I might need to bleed the brakes but that wasn't it. I thought it might be the calipers so I replaced them. That didn't do it. So I replaced the rubber line running from the calipers to the hard lines. Not it. So I'm at a loss. I only have two things left that I can think of. 1.the master cylinder. 2.the break booster. If anyone has any knowledge on this problem PLEASE HELP....Thanks.

 

Is your brake booster the style that is powered by the power steering? If so, when is the last time you flushed the booster?

I've got a hydro booster system on mine (that is powered by the power steering pump). I flushed the system using this method.... Power Steering/Hydro-Boost Flush - Chevy and GMC Duramax Diesel Forum

It made a big difference. Like brand new. However, I waited until about 178k miles to flush mine (way too late).....my brakes have to pumped a couple of times tohave good pressure. So the next thing on my list is replacing the master cylinder....

Hope this helps!