[shad88]

I have a 71 Nova with 4 wheel manual drum brakes. They work, but the pedal goes to the floor. I pulled the lines from the master cylinder and plugged them to test it. Pedal was firm. That's not it. I then pulled each drum and had someone press the brake to see it the cylinders were working and they were. Brake shoes look fairly new. I put back on the drums and adjusted the shoes properly. Next I bled the entire system until the fluid coming through was clean. Everything went fine except that no matter how many times I bled the passenger front I was getting air bubbles. The lines and hoses all look to be in good shape and fairly new. I see no leaks and the master cylinder has never needed to be filled. Anybody have any ideas? If there was air in the line I thought pumping the pedal would bring the pedal back up. Also the car doesn't pull to one side. If there was air I thought it would. Thanks for any help.

 

[russlaferrera]

You answered your question. There is air in the system... Why?

Air is being trapped at one of the bends, or valve. Power bleed the system. Try opening the R/F bleeder and let is self drain into a can, filling the m/c as needed

A bad master/cyl. Pull it off look at the rear (push rod) see if it's leaking/seeping.

When was this condition first noticed? Did anyone work on the braking system?
If so was it done properly?

 

[mintex]

drum brake problems

the problem with drum brakes is that the wheel cylinders can hold air sometimes, rubber brake lines get weak and will expand when the pedal is pressed, need tighter adjustment, front/rear bias valve goes bad, and the master cylinder leak (usually inside the car or in front of the master cylinder.) and also the other possible problem is that someone put a master cylinder for a disc brake car on it. If you have a hard pedal but wont stop check rubber brake hoses. They break down with age and a piece will come loose inside and act like a check valve and not let the fluid get to the wheel. also another problem I have had come thru the shop is the emergency brake spring broke on the peddle and it would fall down when the owner wasn't using it. he loosened them till he didn't hear them scrub but the peddle was about 1/3 the way down. That give him the slop in his adjustment because the peddle could move up and down freely. He thought the brakes were adjusted but they were loose. sounds crazy but strange things happen good luck