brakes on 91 chevy 4X4

Just spent today changing the master cylinder and bleeding the system, and guess what. Still the same. Someone said it could be the brake booster? I know it's not related but found the fluid in the reservoir to be black. I have been told that this is from moisture? Any other advise as you can tell I am running out of options.......

adjust your rear shoes. thats what it took on my 91.

spent the day speaking to various mechanics and I have found that rebuilt master cylinders in 91 chevy 1500 just don't work. Something about them not getting them perfect again. After I bled the system (under pressure) twice I sound that I still had air "boiling" in the front reservoir. Apparently this is a definite sign that the master cylinder is shot. Long story short instead of paying $45 for the rebuilt I shall pay $75 for a new one. Great deal. Looks like talking to mechanics pays off. It's just nice to have mechanics that will share information and help people. On a sad note NAPA has an unwritten policy that they will not return your money only give exchanges. And in my case they will only give me another master cylinder. I can't even get a store credit to put towards other items. Looks like I shall be eating the $45 and learn to shop somewhere else.

[QUOTE=somerset]spent the day speaking to various mechanics and I have found that rebuilt master cylinders in 91 chevy 1500 just don't work. Something about them not getting them perfect again. After I bled the system (under pressure) twice It sounded if I still had air "boiling" in the front brake reservoir. Apparently this is a definite sign that the master cylinder is shot. Long story short instead of paying $45 for the rebuilt I shall pay $75 for a new one (Marvicks Auto 97 St Edmonton). Great deal. Looks like talking to mechanics pays off. It's just nice to have mechanics that will share information and help people. Well I replaced the master and it was instant. So the total tally was only $75 which is incredible. If you want great service with great advice in the Edmonton area get your parts from Marvicks Auto on 97St.