I learned something new last week.... a guy at a cruise-in told me the reason I couldn't get the brakes on my 64 Polara to bleed right and firm up was because I didn't have a residule valve in my brake line. I installed disks 4 years ago and have never been able to get the rear brakes to bleed right and you have to pump them to get them firm. I have an adjustable prop valve and I just figured that was the issue. I'd never even HEARD of a residule valve but found them on Jegs site. I assume I'm probably the LAST to know this so could someone please educate my dumba$$!

Rear discs? residual valves are for drum brakes only, maintains a small amount of line pressure to keep cup/lip seals sealed in wheel cylinders. Not used for disc brakes, will maintain pad pressure resulting in premature pad wear if not removed after conversion.

Sounds like you have too small of a bore for your master, either that or there is must not enough volume.

Correct, they are for drum only. I have four wheel disc on my road runner and couldn't figure out why my rear disc were dragging so much...(you could feel it slow the car down)

I was using a disc/drum MC and never removed the residual valve for the rears from the MC. Took it out and the dragging went away.

Do you have rear discs? Is your MC a disc/drum or a dsic/disc...?

Residual pressure valves come in two pressures, 10lb for drum brakes , and 2 lb for disc brakes. When the master cylinder is lower than the calipers,on a disc - disc set up, the 2 lb valve helps keep a firm pedal.
In the case of a soft pedal, you either have air in the system, or the bore size of the master cylinder is too small, for the volumetric needs of the system. It depends on weather you have power or manual brakes.

Sorry, I should have been more specific. Drum on rear, 74 Dart disks on front, and I believe, a mid 70's Cordoba dual mc. I would think it would have a big enough bore, but maybe not. The mc is obviously higher than the calipers. Did I miss anything else?

Are the calipers correct.Ive seen them where the bleeder isnt in the up position.Pump the brakes and you have a good pedal till you usr thrm again then pump again.I run 69 C body disc drum master with that setup and my pedal is great.Rocky

Residual brake valve may be good for you to have.

What M/C are you using ? We put 74 Dart disc on my sons 72 Dart and used the M/C for the 74 Dart with disc. The redisual valve is in the master cylinder and with rear drum you will first want to be sure you are using a Master cylinder for front disc and rear drum. Ron

The mc is for a mid 70's Cordoba with disc/drum and the calipers are mounted forward with the bleeders on top. The fronts blled fine, but it seems I'm continually getting a little air from the rear. I'm thinking maybe the mc is leaking air somewhere. I don't see any wet spots anywhere.