I have a 1990 K2500 with brake problems. I just bought it from someone that supposedly took it in to fix the back brakes and replace a few parts. According to him when he drove it home from the shop, the back brakes were locked up and smelled like they were burning. So he took it back, they said they messed up the bleeding issue, fixed it, drove it home, and sold it to me.

So I get into it and instantly realize there are issues still with the brakes. The brake light is on, telling me the combination valve differential switch thing has probably tripped, and there is no fluid in the rear brake reservoir.

To make a long story short, my rear brakes don't work at all. My front brakes do, because the combination valve differential switch is doing its job is my guess. I'd like to fix this myself, and I'm not certainly not going to take it to the last shop the other guy used. Does anyone have any suggestions? First off, do I have to remove the master cylinder to bleed it now? How do I reset the differential switch, and whats the best way to bleed the brakes without tripping that differential switch again?

If anyone could help me figure this out I would be very happy.

 

check for leaks, if none bleed the rear brakes. if you get no fluid out of the rear brakes when bleeding...its may have a proportioning valve that needs to be opened to allow the rear brakes to bleed.
https://www.oreillyauto.com/detail/b...r/7853/4607065

if after successfully getting fluid out of the rear/successful bleed...and the pedal still is deep and spongy...bleed the master...crack the lines one at a time and let the fluid pump out....you don't have to remove the line completely.