71 Barracuda, front disc conversion-no pedal

[Tom Doherty]

First post and glad to be on board- I recently converted my front brakes from drums to disc brakes, I can' seem to get the pedal to stay high, Jeg's offers a proportioning valve which the suggest goes on the rear brake line. The master cylinder is new and was working fine prior to the swap. Also any thoughts on a brake booster?

 

[moparleo]

Here are a few things to check. First, when you installed the calipers did you make sure that the bleeder screw is located at the top ? If not, you will never get all the air out. Second, did you adjust the rear drum brakes ? That will control how high the pedal is. Also if you still using the master cylinder that was there before you made the swap, it needs to be changed to a disc brake type master cylinder. The reservoir for the disc brake side will be twice as large as the drum brake side. The larger disc brake piston displaces a lot more fluid than the small wheel cylinder does. The proportioning valve changes the difference in pressure between the front and rear brakes. You don't want the brakes to lock up when braking hard.

You said that you recently converted to the disc brakes. Was this a new kit ? Or junk yard parts ?

 

[Tom Doherty]

Thank you for responding, This is anew kit and the bleeder screw is a the top, the rear brakes were bled, The master cylinder is a replacement original for drums and your comments make sense about he two sizes. If I swap out the master cylinder and add the proportioning valve do you recommend a booster ? I am considering doing the rear conversion, will this require another Master cylinder- should I wait ? Thanks again for your feed back

 

[moparleo]

I would go with power brakes either way. Another recommendation would be to switch over to s/s braided brake lines. This will help you get a more firm pedal. The rubber hoses will expand under high pressure causing a spongy feeling. If the conversion was a kit, that mfg should have the other parts that you will need and more likely will matchup with what you bought already.

 

[Chryco Psycho]

If you have power steering I would look at converting to the Hydroboost system over the vacuum booster unless you want the original look , Willood has a better 5 line proportioning valve factory style with the adjuster . The Master needs to be swapped as well for disc but will have to be different again with 4 wheel disc so why not swap the rear brakes & master at the same time . You said you bled the rear brakes but did you adjust them ? If they are not adjusted properly the pedal will be low. You say you have a hard time keeping the pedal high is it low on the first pump & higher if you pump fast or is it sometimes high & drops after a few pushes on the pedal ?