I have a 1993 Z71. Owned 15yrs. Brakes have not been good for the last 10yrs. Everything about the rear brakes needed replaced. So i decided to do a disk brake conversion. Ordered kit and put together. I have bled brakes for years, so this is not my first time. I have replaced master cylinder also and bench bled. The problem is i can't seem to get fluid to the Left rear wheel. Right one finally bled ok, but the left one just keeps having air. I pulled the brake line loose from the caliper put the vac pump on the line and still only a very,very small amount of fluid will come out. It seems as if fluid is not coming to the left side properly. Does anyone know it there is another valve or anything in the line that would prevent fluid flow. I have never had this kind of problem bleeding brakes before. Any info would greatly be appreciated. I will after i solve this problem put pics on here about the conversion to rear disc brakes.

 

Interesting...does that kit keep the same rear brake line?

 

Yes sir. Same brake lines. Checked with the company to see about needing a proportional valve, but was told so far none of their customers has had to use one.
Update on my brake bleeding problem. I have disconnected the lines from the master cylinder, each wheel and used pressurized air and blown thru each one and they all are open. GM doesn't know or chose not to tell me if the (combination valve or the dump valve) could be the problems.
I'm still not getting any fluid coming thru the rear lines.
Could it be the new Master cylinder??? I'm lost on this one. The old vehicles were so much easier than all this electronic crap.

 

The proportioning valve could be causing problems. I guess the brake lines are good? Try a Mighty Vac?

 

Yes lines are good. I finally got to talk to a friend of mine that used to work for a local chevrolet dealership. And he is good at it. He said being as i had all the lines loose and flushed all the way to the back of truck that i would have to get fluid thru the combination valve and dump valve first or i would never get fluid to the rear of truck. So i followed directions and got fluid thru each valve. Now the next task is getting all of that air out of my lines. I have used a vac, but there is more air in the lines than i imagined. Still bleeding. I let truck set several hours then go back and bleed some more. Seller of the conversion kit (did) inform me that getting all the air out of the calipers with e-brake kit would be hard. So i'm still bleeding daily. I will put pics with conversion after all air is out. I don't want to display pics till it is job is done right. Thanks for all the input.