sam0822
Newbie
I have a 98 gmc c1500. I’ve been have bad brake issues since I bought the truck about a year ago. Recently I found that my master cylinder was cracked and replaced it and all new stainless brake lines. It would stop alright for a little while then the other day I started hearing a hissing noise when braking and have been having to pump the pedal multiple times to stop. The brake fluid was black and small amounts of debris coming out of the bleeder valves when bleeding. Now I’m thinking my brake booster could have gone bad. Any other suggestions of what the issue could be? Also if anyone knows upgrades to prevent this from happening in the future?