Do you have a little bit of "free play" when the pedal is all the way up?  If not, the actuating rod may be too long and not allowing the cylinder to back up far enough to take in fluid.

i may have an answer for you if the master is second hand check the bottom piston is not stuck in the bore i have had this happen on master cylinders before usually the front wheels wont bleed & no fountain in the resevoir you cant feel it pressing on the brake pedal it will feel like both pistons are moving as the spring between the 2 pistons will still compress have also had it happen on a new master cylinder that had sat on the shelf for a while at the parts store & was bench bled.

Simply take the M/C to your bench and install plastic tubes (or old brake lines) from the brake line outlets back to the reservoir.  Fill both sides at least half way, then pump the piston at least thirty times.  You will see tiny air bubbles in the fluid, so the idea is to do this relatively slow.  Keep pumping until the bubbles stop.

The M/C has lots of nooks and crannies inside.  Doing this on your car will require LOTS of brake fluid (because the tiny bubbles  keep coming for many strokes).  On your bench, return tubes recycle the fluid so there's less waste.

You are smart to go down from 1-1/8" piston.  That's a lot of area, and I never met a brake system that required so much volume.  Reducing the bore to 1" will give your foot a 20% easier pedal.  Reducing to 7/8" will ease the pedal by 40%!  My '55 Customline came with a 7/8" M/C.  It pushed four shoes without a power booster, just fine.  If you keep up with your brake adjustments 7/8" is the way to go.

Hope this helps.  - Dave

It's a couple clear tubes with hard plastic tapered ends (you just shove them into your output holes).  Here's another set:

This kit has "exact fittings" but it's the same thing, two little plastic tubes.

Put the M/C in a vise and start working the piston in and out, like I said, about thirty times.  When the bubbles stop, you're ready to mount it in your car.

-  Dave

                   I've got a 1" bore(manual) in my '60 with 4-wheel disc and it stops o.k.

                   but, the pedal is hard and takes a "good" push to stop it. I'm curious if

                   your deal will help..... Thx Bill

Regarding all this discussion; bench bleeding is easier to do, than to talk about it.

Rebuild your M/C if you think it needs it, then bench bleed it.  Same goes for new Master Cylinders.  Here's a good web site explaining 'bench bleeding'.  There isn't much to it:

http://www.misterfixit.com/brakbld1.htm

This is a method using old brake lines.  Notice the tubes are below liquid level so air has only one way to escape.  I use full strokes when bench bleeding.

Your brake pedal calculations are good except for one thing.  When your shoes or pads are adjusted correctly, your brake pedal will hardly move.  The piston diameter won't mean much at all if the pistons hardly move.  Your travel will be at the top of your pedal.  When you get your M/C installed, bled, and you adjust your shoes, you'll see.

- Dave

Charlie, sounds like your brakes are working just fine.  You should fine-tune your system by adjusting the M/C rod, just so it jiggles.  That will ensure a full retract on the M/C.  Also, pick up your tires and adjust your shoes.  I don't know how new they are, or if you have self-adjusters.

Spinning your wheel by hand, the shoes exert a slight drag.  Adjust all four drum brakes to this "feel".  They should never pull to one side.  As new brakes seat, they go out of adjustment fast because the arc of the shoe is conforming to the arc of your drum.  Before too long, they will mate perfectly and you will gain more surface area on each brake.  Disk brakes don't have an arc, so this only applies to drum brakes.

Disk brakes don't retract either, they relax.  Because they don't retract, there is no brake adjustment.

Charlie, take pictures!  Get a cheap digital camera and store your before/after pics on your computer.  I take 10 pictures of everything.  The ones I don't like, I delete.  So many times, I wished I had taken more pictures at different angles.  Sometimes I refer to a picture for a completely different reason than I took the picture for.  The moment it takes to snap a photo will save you from redoing backwards Pri/Sec shoes, or adjusters.  We've all been there and done that.

I'm glad you got things going again.  To tell the truth, I never use a vise for bench bleeding.  I do it on my drill press table, and back up the M/C against the back post with a 2X4 in between.  I use a long phillips screwdriver, pushing on it with my belt buckle.  My hands are free the whole time.  - Dave

Ever since then, I paid closer attention to detail.  I had a '64 Tempest that was due for its first set of new shoes.  I noticed the right-rear shoe was perfect, just like it came out of the box, but slightly rusty metal.  I discovered the cylinder had NO hydraulic hole from the inlet to the cylinder bore.  Back then, I bought a new cylinder.  Today, I would drill a simple hole.

Funny, I did a lot of brakes since then, and 'lost sight of' most of them.  A relative will remind me of when I did their brakes while they were in town for a visit (usually on a car that's long gone)...

Charlie, use that 1" bore M/C.  It's new, and it should work perfectly.  Your leg will thank you for using at least 20% less pressure to stop your truck.  My '55 Customline came with a 7/8"-bore manual M/C for 11" X 2-1/2" shoes.