I have new everything. I clamped off all the soft lines, and I have a hard pedal. released the rear line, pedal still good. I reclamped it. I released the pass. side front , pedal drops. after a pump are two it firms up, but I can turn the tire by hand until, the pedal is pumped a few more times. when I release the driver side line pedal drops some but recovers after a pump. the brakes while I drive it will never grab hard. even at 2 mph with repeated brake applications and a firm pedal. I have done many bleedings , third master cyl., bench bleed all. the last one using both methods( with tubes and pluged). I have a hard pedal with line pinched, checked for bleed by on master. booster passes all test I have found. holds vacuum 10 to 15 mins after shut-off. could the round metering valve be bad? is there a way to test it? it's new but that means sh?t.
any ideas would be helpful. next step is do it all over again. or do a way with round metering valve and buy a new combination valve and go that route. or maybe cut a hole it the floor and go flintstone style.
thanks for any ideas.

Tell you one thing - NOTHING has given me a more firm brake pedal than ditching the OEM rubber lines for braided SS.

I'm no pro but I'll see if I can jar some thoughts.
If you have drum brakes did you adjust the brake shoes good? If you don't have them tighten enough you may not have pressure against the drum. You have to run the shoes up until you have good resistance when you rotate the wheel.

That would be my start.

I would usually get them close that way and then back the car up a few times and let the self adjusters finish it.

well I guess I left one thing out. went from power drums to power disk on front. rear are drum. they are adjusted as far as possible and get the drums on. car stop better backwards than forward.
my thinking on the round metering valve being bad. if I read correctly. it holds some pressure on the front calip. so the pads retains close contact with the disk .if it is not working then the piston draws back further than should. causing more travel to apply. or am not pushing on my master far enough, this is something to check!!

I guess we would need more information on the conversion then.

Did you buy the whole conversion kit with a new master cylinder and the proper rear proportioning valve?

This is a long shot, but could you have possibly inslalled your front calipers incorrectly?...left to right, and vice versa? The bleed valve should be on the top of the caliper...not toward the bottom.

Pushrod too short? Disc brake piston will not back off the rotor when you let off the pedal. It will always have a bit of contact and also some consequent drag. Just the way they are designed.

Good rears, bad fronts?
Sounds like either wrong master cylinder or proportioning valve.

Since you stated you have all new , we're going on the assumption it's new everything and none of the old stuff is still being used
The valve you refer to is the residual pressure valve, which keeps a bit of fluid in the lines to keep the shoes from pulling too far away from the drums. This is not used in the front disc circuit but has caused some grief for those who have replaced the front drums with disc and not taken the valve ball out of the system, Usually they are in the outlet ports of a drum/drum MC.
You've bled everything
You clamp off all the lines and your MC has good pedal pressure.
You unclamp your front brakes and have no pedal pressure and your front brakes don't hold.
Sounds like the MC is not supplying enough volume of fluid to move the pads against the discs.
This could be due to a MC that is not compatible with the front brake calipers. Just doesn't have the physical ability to supply the volume required to move the cylinders in the calipers.
Or, the MC piston is not being moved it's full travel thus not moving the required volume of fluid.
It would take very little travel of the pedal and very little volume of fluid to get pressure in the front lines with them clamped off compared to the amount of fluid it takes to move the brake caliper pistons.
Is the MC a one inch dia. or larger piston?
is the brake push rod in the correct hole in the brake pedal lever?
Is the push rod the correct length?
Or there is still air in the front circuit.
Or the system is not connected, plumbed, correctly.
Or you have defective parts.
Or you have parts that are not compatible with each other.
You should have a metering valve and a proportioning valve. Or a combination [metering, proportioning, differential pressure] valve.
As the front pads are always slightly in contact with the disc they are in the position to activate with little increase in fluid pressure. The rear shoes on the other hand take more to activate as they are not in contact with the drums. The return springs pull them slightly away and it also takes more fluid to move them than the front discs. The metering valve doesn't allow any pressure to the front circuit until the rear circuit builds a small amount. This is called threshold pressure. When the threshold is reached it allows pressure to the front system. This causes the rear brakes to just start to engage before the fronts. It helps to keep the car straight during braking. If the metering valve is defective it may not be letting pressure or only a reduced pressure into the front circuit after the threshold pressure is reached.
The proportioning valve reduces pressure to the rear brakes. It takes less pressure to lock up the rear brake than the front brakes. As the car de-accelerates the weight is transferred to the front requiring more braking power at the front and less at the rear. If this valve is connected backwards it will be reducing the pressure to the front and not the rear.
The pistons not moving in the calipers due to a mechanical problem could cause lack of brakes but the fact you have no pedal pressure would most likely discount that.
The fact you can get pressure with the front lines clamped and not with them unclamped points to air in the calipers or just not enough fluid supply.
If you have everything connected correctly and there is no air in the system, I would say the MC is defective or you have mis-matched parts.
If you do the Flintstone thing cut a hole for the passengers, every bit helps.
But, I could be wrong.

Nicely done Bluebird428-great explanation! This is why we have such a great site, knowledgeable people helping others out when they just want to beat their heads against a wall....

Hey Sled,
I may be a lot of things but I don't know if knowledgeable is one of them. I'm just repeating most of what I've learned on this site. I had brake problems a few years ago and got help from fellow members. After I took mine apart to the last bolt I learned a bit more.

On a side note, I like your signature. I just lost my Dad who was wounded three times in WWII and we just celebrated his war bride and my mother's 89th. God bless them all.

Thanks BlueBird,

I think that's how a lot of us have learned, lol. The guys that have been into these cars for years are like walking dictionary's.

We went to a St. patty's day parade yesterday, and I was the only one clapping and whistling when the Vets and the Army went by- so sad. Everyone else was interested in the floats that had the music pumping right in front of them.

So sad... Those Army kids didn't show any remorse though- they were smiling !!! The Vets actually looked right at me and tipped their hats- that was cool. Thank God for men like your Dad- we would be a totally different people if not for them.

nonothing, did you ever get your brakes figured out?