My 81 F150 had an empty brake reservoir for several weeks while I changed the front calipers, wheel cylinders and master cylinder. I bled the master cylinder, connected all my brake lines back and tried to manually bleed the brakes. I started with the rear brake (rear right) and discovered there is no fluid going to any of the rear brakes (all rear break lines are dry). I know the master cylinder works, I can see fluid coming out in the rear brake line. I was not able to check the proportional valve and the junction block on the top of the axle fluid. I was not able to undo any rear brakes line connected to them. I know I didn’t have a problem with them before changing the rear wheel cyclinders. How many times does one need to press the brake pedal to bring brake fluid to rear breaks? Can I use an air compressor to blow air to clean the lines and the proportional valve? (Disconnecting the rear brake line from master cylinder on one end and disconnect the other ends of the brake lines from the wheel cylinder and blow an air from air compressor.)

Does any one have the same situation? Any advice?

 

is there a kink in the line?if so you might need to cut and splice or replace the line.also check this connection to the rear brakes.they sometimes get clogged,bad valves,rings going bad,sometimes just some stupid reason for a problem to occur.hope some of this might help you in some way.

 

There is a very small brass pin in the proportioning valve that must be pulled out and held while the bleed process is happening.
This allows fluid to go to the rear brakes.

 

You've got a huge amount of air in the system. get a piece of plastic tubing with the same i.d. as the bleeder valve on the wheel cylinder. lossen the valve on the wheel cylinder, slip the tubing (about 18" to 2' long) over the valve, stick it into a glass jar about a quarter to half full of brake fluid and pump till the air is gone. while the tube is still in the jar (DON"T take it out yet), tighten the bleeder valve. don't let the jar go dry and don't let the master cylinder go dry. just keep going around till the brakes are done. Do it this way or get a bleeder ball, which is a whole lot easier. A handheld vauum bleeder will do the same but it's a little harder to use.

 

RUSSELL SPEED BLEEDERS
Do search or get them at Jegs.