1969 Coronet Brake System

[markbob]

Hey all....

have a 4 wheel power drum brake system....

I have all new stainless brake lines and wheel cylinders....

the proportioning valve and master cylinder are original to the car when I purchased it...

I hooked everything up, and bled the front brakes....then I moved to the rear....everything was fine until the rear of the master cylinder began leaking and fluid ran down between the master cylinder and brake booster....

I purchased a new master cylinder, and installed it....

today I filled it up and began to bleed the brakes....I bled the front and it appeared to go fine....

I tried to do the rear brakes and there is no fluid coming out of either side....
I disconnected the ss line from the rear flexible line.....no fluid in there either(other than a few drops).

I moved to the proportioning valve, and loosened the line that goes into the top of it from the master cylinder....a hiss and some fluid....

I tried the front brake line ports....got fluid to come out....
I tried the rear brake line ports, and nothing....not a drop

any ideas? I am thinking it's either a bad master cylinder, or there is a blockage in the forward line that sends fluid to the rear brakes....

Help...please!

Mark

 

[ws27]

I'm having trouble keeping up with you LOL : http://www.dodgecoronet.com/forum/showthread.php?999-69-Coronet-Brake-System

 

[Propwash]

Couple things Mark.......You don't have a proportioning valve, you have a distribution block. All that block does is distribute the fluid to the different braking circuits. A proportioning valve actually proportions the amount of fluid/pressure to the front/rear. Just mentioning it in case you ever go to replace or troubleshoot that part. Second, did you bench bleed the master cylinder? Like mentioned, good place for air to be trapped. If you havent done so, you should. 3rd, is the car level? Actually makes a big difference. 4th, you should start your bleeding from the wheel furthest away from the master and work your way to the closest. Good luck

 

[PUNKN8R]

Whenever I do extensive brake replacement or work in general I always bleed master cylinder first then open all bleeders and let them gravity bleed til I have a good drip from all four corners then I'll close them start the bleeding at the wheel farthest from the master cyl. to the closest being last. Never a problem after that. Good Luck !