1997 Chevy Silverado Z71 350 5.7L V8 200k miles I'll just get right into the story. I'll appreciate it very much if you actually take your time and read all this and try to help me out. Thank you. Checked my brake fluid one time. Put the cover back on. Checked it later to find out the seal wasn't sealed right. (I now know to put the seal on the lid THEN put it on the master cylinder haha.) I was having some problems with my brakes. Stiff pedal sometimes, then it'd be okay. So I got sick of the problem and my dad seemed to think it was the brake booster. So we went the the junkyard and pulled a booster and master cylinder (PITA), paid $75 and went on our way. After we bought it my dad was saying how we should try to do a brake bleed just in case. So we did a brake bleed (it needed one, the fluid was very dirty) and it fixed the problem it seemed. Well that lasted roughly a week and the problem started to come back. So I decided to bleed the brakes again. The brake fluid was just a little dirty, but I figured I'd try it. No change this time. The brake pedal is still very stiff especially at first start up. Sometimes I can barely brake unless I push really hard on the stiff pedal. So before I go spend a bunch of money on (a) part(s), what do you guys think? Let me know if I need to go further into detail about something. BTW, the booster holds vacuum and the check valve is working. Thanks again!