Brakes to soft after conversion

[gdizzle]

Any help. I did the scarebird front disc conversion on my 66 dart. rear it still the 9 in drums.
I changed out the master cyl with a newer 2 chambered version (1 for front, 1 for back).
I even install an adjustable valve that goes to the rear brakes, just in case.

I thought it was all fine, then I had to replace the rear diff gears, which meant pulling off the axles. Now reinstalled, had to adjust rear brakes a little.
But now it just doesnt stop fast enough. And I cant even get it to skid.
For experiement I turned the adjuster I installed that feeds the rear, and I turned it way up so the rear will barely stop just to see what happens. When I drove it it did seem to stop better which confuses me ho less rear pressure means better stopping upfront?
Any ideas here??
Fluid is in great shpae, properly bled, .
Is it possible that rear brakes are too tight??

 

[DentalDart]

Make sure all lines are super tight with no leaks or air able to get in.

Bench bleed master cyliner before installing. This can be done while on the car still, its just a lot more messy. If any air bubbles get trapped inside MC apparently you can't get them out through regular bleeding.

Make sure mc rod isn't to long, sometimes you need a spacer between firewall and MC to ensure the rod doesn't bottom out in the MC.

Make sure the bleeders on the calipers are on top, inline from the brake hoses below the bleeder.

Adjust rear brakes very tight, the pads should be dragging on the drums.

Bleed brakes from passenger rear, drivers rear, passenger front, drivers front.

If all this doesn't work, then you have a bad MC or are getting air in the line somewhere, replace the hard lines. Once I replaced my hard lines my brakes started working properly and I could get them to lock up the tires.

 

[67Dart273]

"Did it ever work" correctly (after the conversion?) If not the master may be too large bore. You shoes or even pads could be glazed. The shoes may be effectively too small if the rear drums are worn. You need to have them arced. Good luck finding someone who has a machine, anymore. Regardless, though, you should be able to get one end to slide. How is the pedal feel?

AND IS IT power or manual, and which was it origininally?

 

[dano]

back up and pump your brakes to adjust the rear.

 

[Slantsix64]

Disc brake cars use 70 percent of stopping power up front and 30 percent in the rear, this is why they have a prop valve to limit stopping power/fluid flow to the rear so the front handles all the braking. Dont quote me on the 70/30 but something like that