Bleeding Brakes on a body

have discs all round with mopar after market master cylinder
when I bleed the front pedal goes to floor
when I bleed the rear pedal goes about 3/4 is this correct??

While bleeding, or after you're done?

while bleeding is this right

What make and model are you working on and what method are you using to bleed the system.

67 barracuda
pedal down open bleed
close bleed pedal up

first I would put a block of wood under the pedal to limit its travel to the normal range (not a dealbreaker but it keeps the cups in their normal worn range of travel in the bore). not sure why the rear bleeding wont go down, I would try it on both of the rear bleeders (which you have likely already did) & if no change then possibly crack the T hose fitting back there & repeat. are you running a prop valve of any kind?

he has 4 wheel DISCS

So not stock.

And what is "mopar after market master cylinder"?

Who knows what you have so who's to say how it should act.

Some details would be nice

yes I am running a stock brass proportioning valve have been running this system for some time just changed some brake lines and really struggling to bleed them just cant remember if pedal was doing this before.
mopar performance m cylinder

the cups I am referring to are the MC cups. on a MC with some miles I like to keep those cups in that normal worn area when bleeding (not a dealbreaker but does extend the life of the piston seals). I would crack the line just upstream from the prop valve see what develops. does this valve have the pin that you pull out to bypass the proportioning? EDIT & a block of wood gives your helper more control over the pedal movement & on discs I like to have him pump it several times then with good verbal timing I open the bleeder on his last downstroke as this agitation gets the air out better but we ain't there yet, first we gotta find out what is going on.

Last thing I would run is a stock combination valve on an all disc setup.

hey Supercuda thanks for info can you tell me how you would run this system cheers

Not without a lot more info than you've given.

Since no A body came with 4 wheel discs stock I cannot begin to guess what you have or what you may or may not need. Other than not needing a stock combination valve in an all disc system

I would bypass the prop valve & see if it bleeds out (I think it will) then take it out for a spin & see how the proportioning feels.

ok here we go
I have strange ss struts on the front with 4 piston calipers.
On the rear I have strange single piston calipers
I am using the brass splitter box I think this is stock, not sure if this is a proportioning valve ?
spent some time bleeding these pedal still feels a bit spongey
thanks

sppongy is air. I would bleed the MC first

On a good 4 wheel disc system Master Cylinder bore and caliper piston diameter come into play for optimal performance. You would be better to not use a proportioning valve and simply plumb in an adjustable one on the rear brakes. If you simply swapped out hoses to new from what you had before it sounds like there is still air trapped somewhere...
FWIW sometimes I open the bleeder and then have someone depress the pedal and then close the bleeder during the first attempt at bleeding. Kind of what Robert touched on earlier...