It seems like the rear brakes are not working on my 1996 Jimmy. It takes much more pedal pressure than normal to stop the vehicle. When I tried to bleed the brakes, I could only get a little bit of fluid to come out of the rear bleeders (the fronts were fine). Is there a trick to bleeding the system on these? Could it be the master cyclinder? any other suggestions?

 

My guess would be the master cylinder.

 

What would cause this? Is there something in the master that could get stuck?

 

Could be the MC. It has two lines one going to the front and one going to the rear. Maybe the seal went out for that one and only the front is working.

 

If there was a bad seal in the Master Cylinder, wouldnt the pedal go to the floor? Could it be a proportioning valve problem? How do I diagnose?

 

I think I have the same problem on my 93 Jimmy. it takes a lot of effort to push the pedal in to stop the truck. The front pads are worn prematurely too. I don't think ABS equipped trucks have a proportioning valve. I couldn't find one on my truck. Anybody else have some ideas what our problem might be?