Tranz Zam Posted January 27, 2018 Report Share Posted January 27, 2018 So I'm having issues getting my brakes to bleed. I installed all new stainless steel lines, new rubber hoses, and a new master cylinder. Right now I'm only getting fluid to the driver front caliper. The passenger front is getting a little fluid (just dribbles), and the rear aren't getting any fluid. I had a friend cycle the ABS with his scan tool, and still have nothing. I then tried to get the fluid to pull thru with a vacuum bleeder, but I still got nothing. So today I removed the two feed lines going into the ABS box, and noticed only one was pushing fluid. I removed the rear cap on the proportioning valve and noticed the pin was pushed out, so I pushed it back in. I still cant get anything out of one the lines. Does this sound like a bad proportioning valve? I replaced the ABS box with a good known unit, but I still have nothing getting to the rear calipers, and a very weak stream at the passenger front. This is driving me nuts, so any help is appreciated! Thanks guys! Quote Link to comment Share on other sites More sharing options...
Tranz Zam Posted January 28, 2018 Author Report Share Posted January 28, 2018 I think ACDELCO 21998450 is the correct part # for these trucks, but I'm not 100% sure. The SS seems to have a hodge podge of parts that seem to be borrowed from other GM trucks, which can make things confusing. It was fun figuring out what master cylinder was the correct one. Quote Link to comment Share on other sites More sharing options...
Tranz Zam Posted January 30, 2018 Author Report Share Posted January 30, 2018 Sooooooo I replaced the proportioning valve with a new one, and now I have brakes. I decided to take the old one apart, and the internal valve was stuck in the closed position, blocking fluid from getting to the ABS box, which I guess was also supplying the rear brakes. It was full of terrible looking fluid too. I now have brakes, with a powerful stream of fluid exiting the bleeder screws. The passenger front has a weak stream compared to the rest, but its working because I can hear the pads moving when the brake is pressed. Strange, but at least the truck stops again. Quote Link to comment Share on other sites More sharing options...
Downeast Johnny Posted February 2, 2018 Report Share Posted February 2, 2018 Good to hear that you got it figured out. You have added to the data base as far as symptoms of a bad proportioning valve goes. Quote Link to comment Share on other sites More sharing options...
SuperStock Posted February 8, 2018 Report Share Posted February 8, 2018 Glad to hear you got the issues sorted out. Is the passenger side still weak? Quote Link to comment Share on other sites More sharing options...
houston05tx Posted February 8, 2018 Report Share Posted February 8, 2018 Quote Link to comment Share on other sites More sharing options...
gcosse05 Posted March 26, 2018 Report Share Posted March 26, 2018 Im about to do some braided lines on my truck and I'm probably going to go ahead and change this after seeing your problems. My truck sat for a year and now that Ive got it running again I've got a caliper sticking. Im about to spend a crap load of money . But I want alllll new stuff. Im not gonna mess around with it. Ripping it apart tomorrow. Thanks for sharing. Quote Link to comment Share on other sites More sharing options...
Tranz Zam Posted March 27, 2018 Author Report Share Posted March 27, 2018 Glad to hear you got the issues sorted out. Is the passenger side still weak? Sorry for the late reply. The passenger side was weak. I brought it to my buddies shop, and had him bleed the system with his scanned and a powerful vacuum bleeder. It got the passenger side working properly, and the pedal is much better now. Im about to do some braided lines on my truck and I'm probably going to go ahead and change this after seeing your problems. My truck sat for a year and now that Ive got it running again I've got a caliper sticking. Im about to spend a crap load of money . But I want alllll new stuff. Im not gonna mess around with it. Ripping it apart tomorrow. Thanks for sharing. The brakes on these trucks are a giant pain in the ass. When you open the system completely (like replacing all the steel lines), bleeding becomes your main battle. Bolting everything together is the easy part. Quote Link to comment Share on other sites More sharing options...
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