I recently switched the front brakes on my 62' Chrysler over to disc. I used adapters from Scarebird to mount Chevy truck calipers. The rotors are from a 70's Volare. The rear is still the stock drum setup. This car had a power setup, and I utilized the stock booster. I used a prop valve and master cylinder from a 78 Dodge truck.... Everything is brand new except the proportioning valve and the booster.

Ive bench bled the master before installling it. I bled all connections and bleeder screws. The pedal will not stay firm when pumping it up. It still feels spongy. It doesnt fade to the floor quickly. Am I missing something? Should I try and attempt something else?? Thanks

AIR... If the M/C is bench bled I'd plug the drum half of the M/C & concentrate on getting the air out of the disc half then w that taken care of hookup the rear drums(& bleed them if still spongy). Having the bleeder screws open too far when your helper lets up on the pedal is a common way that air keeps getting pulled back in.

Ive bled the system a lot. I am getting a steady stream of fluid from the bleeder screws...Do not see mt obe getting anymore air out. I made sure the bleeders were completley tightened before allowing the pedal to come up.....

Are calipers on the correct side of the vehicle, so that the bleeder is all the way at the top, so the air will escape during the bleeding process?

I've been working on my brakes lately too. I have mostly all stock Dodge parts- Disks up front and drums on the rear. About 10 yrs. ago, amongths other things, I replaced the master cylinder (but not proportioning valve). I have never since been able to get the sponge feel out of the initial brake pedal stroke. Since then I've read/heard some master cylinders were better than others. To get the best brake feel, good feel about 1/3 from top, I have to have the drum shoes adjusted so I hear them rub on the drums no skips. And there is some drag while turning wheel by hand. But the truck rolls fine on the road, trans slip on tach. is the same as when shoes were not adjusted up tight.

I recently went to a shop to have my system pressure bled, before adjusting up the shoes. I had poor braking due to a low brake pedel. Using the pressure bleeder to change all the fluid they had less pedal untill they had another mechanic pump the brake pedal and bleed manually. I did have air in my lines due to a (believe it or not) loose and seeping rear brake line at the rear axel vent junction, and the corrosponding rear wheel cylinder backing plate botls were both very loose with the front of it wet. So, I fixed that and cleaned up the shoes and drum etc. But I still had only slightly better but still poor brake pedal feel.Only after I adjusted the rear shoes as said above did I at least, once again, achieve good pedal feel 1/3 from top.

I'm wondering, Would a better pressure bleed fix our problem, or is it due to a poor quality master cylinder?


Now the truck stops easily dispite extra weight, with traffic usually around the 1/3 pedal area. But I would prefer a harder pedal feel from the top as I think I rember having so long ago.