i have 70 chevelle i replaced everthing in the rear drums when redoing my frame. i replaced mastercylinder and booster. i have front brakes but cannot get my rear drums to work. i attempt to bleed them, i have fluid to the bleeder but seems like there is no pressure. when i bleed it looks like no air is in with fluid. with the brake pedal pressed i can turn the tires by hand. any and all help needed . thanks!

To start off with. How well are they adjusted back there?

the shoes are adjusted very close. but for some reason the cylinders dont seem to expanding the shoes.

You may want to check the rubber brake hose that connects to the rear brake line manifold. It's near the top of the rear end and can become clogged through the years. That has caused me that same problem on both of my 70 models. It will let enough fluid through to bleed, but not enough to engage the shoes completly.

Jim

I had the same problem on my '72. It has something to do with the proportioning valve

Make sure there is enough "free play" in the brake pedal. Too tight on the pushrod will not allow the M/C to return to a neutral position and the rear brake chamber of the M/C piston will not recharge with fluid.
Ask me how I know... :clonk:

how do you know??

how do you know??
Because the adjustable pedal pushrod was too long on my '70 when I converted to manual brakes and I couldn't bleed the rears...no fluid would come out.
Shortened up the rod and was then able to bleed normally.

well i readjusted my brake pedal,to make sure i had the best travel on the brake rod. removed the rear prop valve,backed the plug out of it all looked good. i could blow air through it easy. removed the rear brake hose which is new . fluid seems to be flowing through it well. fluid seems to be flowing threw everthing ok, it just want pressure up. and my dash brake light comes on when i press the pedal. i am open to more suggestions? i am thinking about replacing the master cylinder again. it was new when installed and not driven many times. is there a way i can rig up a pressure gauge on the rear lines and check the pressure? thanks for any and all help! michael

This is a timely post. I rebuilt the wheel cylinders on my friend's '71 GTO this weekend, and put in a new master cylinder. Went to bleed them today, only one that will get any fluid at all is the driver's side front wheel. The rest are dry, with a solid pedal and the bleeders open. :rolleyes: Car's been sitting for 7 years, I'm puttin' my money on the proportioning valve being stuck. The master is a direct replacement, so I doubt the rod length is the problem, but it's something to check. Anyone had any luck rebuilding their prop valve? I've never needed to go inside of one, just wondering if it's serviceable, since I don't see any kits for them.

A friend is having the same problem with his rears. Any final solution on these problems from above?

Last year I dedid complete drivetrain on my 67 Elcamino, rear got new brake hose, wheel cyl, shoes, springs along with 12 bolt. fronts were converted disc set up and in good shape. I had to move p-valve higher and over top frame, made all new brakes lines on front with new rubber hoses. now the fun began.....2 qts of fliud thru system..power bled, suction bled, pump till wifes leg feel off. still no rear brakes. finally a friend told me to jack uo rear end as high as possible. I used 7 ton jack stands as high as jack could lift. left it sit for 24 hours...rebled..had brakes ever since...don't know why! but it worked! jay

A friend is having the same problem with his rears. Any final solution on these problems from above?

If you have a prop valve, it might be bad like it was the case for this guy (http://camaros.org/forum/index.php?PHPSESSID=9uknro3r6i2jd1t70vahv2ilo3&topic=5952.0).

finally a friend told me to jack uo rear end as high as possible. I used 7 ton jack stands as high as jack could lift. left it sit for 24 hours...rebled..had brakes ever since...don't know why! but it worked! jay

That's because air was trapped in your m/c. The m/c has to be leveled to be properly bled. That is the purpose of bench bleeding it before installing it. But raising the rear end of the car will do the same.

I agree but I bench bled it off car before and during...Just know it worked that way...I'm happy J