I sprung a leak in my wheel cylinders yesterday and after replacing both rear cylinders i couldn't for the life of me get them bled
Well after a lot of swearing and cursing i came back to this site to see what i can find,and lo and behold someone here mentioned the button on the proportioning valve.I had forgotton all about,(i'm over 50 hahah)
I had changed that valve years ago,and i also remember now that i went thru this before
Could have saved me a lot of time by checking here sooner
Keep up the good work here fella's
Thought i would post just to let other people know that that button must be depressed when bleeding rear brakes
The button is about the size of a pin head on the end of the valve
Only if you have this style of valve
Hope this may help others

I had a monster of a time bleeding my rears when I did a manual disc conversion. Pumping the brakes didn't work well enough, vacuuming didn't work well enough. I finally had to get a pressure bleeder canister and do it with 15psi. What is your system, and what is the proportioning valve configuration? Mine is attached to the frame down by the side of the transmission bell. I hope I missed something here and I can improve my brakes....