There are several ways to do this job.
I would not do the whole job at once. I would do each job by itself.Start at the top, and work my way down and to the rear.
You will need a helper.
Start with a bench-bled M/C. Installed. Top it up to about 1/2 inch from the top.
Move to the Proportioning-valve(BTW, why are you changing that?It almost never makes trouble.)Block the brake pedal down about 1 inch. This will prevent draining the M/C through the compensating port,during the valve removal.Spread out the rags. Protect your paint. Keep the brakleener handy as well as clean paper towels.This will be messy. Remove the 5 lines from the valve, and swap in the new one.Do not tighten the lines,just snugged.
Now lets gravity-bleed that puppy. Ok, release the pedal depressor. Crack the two large fittings at the topside of the valve. Let the M/C drain down about 1/4 inch or so, while observing the fittings.You want to see both lines bleeding clear bubble-free fluid.When this time comes,snug them up a bit, but let them seep a bit.Top up the M/C. Then crack the other 3 fittings. They should run clear almost right away.Then start snugging fittings,from the top down.Top up the M/C.
Next is the pedal test.But I go for lunch first. This lets any tiny bubbles rise to the top.They usually accumulate right at the top fittings.So, after lunch, I crack those fittings,one at a time.While theyre cracked I depress the pedal a bit to force just a bit of fluid out,and snug the fittings while the pedal is still depressed.Then release the pedal.Next,with a flashlight, I eyeball the compensating port at the bottom of the reservoir, while the helper gently,slowly, begins to stroke the pedal.Each time the helper releases the pedal, the fluid will return to the reservoir, perhaps in a fountain.The pedal release has to be slowly, and or a little less stroke.The shoe-return-springs can make quite the fountain.So start off with very short,slow-release strokes. Sometimes the fluid will bring bubbles with it. I call this "tickling the pedal". So tickle it,til no more bubbles come.Put the top on, and secure it . Depress the pedal, looking for a hard pedal.If the pedal is hard,you can final-tighten all the fittings and you can move to the wheel cylinders.But if you didnt have a hard pedal before, you may not get a hard pedal after.So, we will have to get to that after the new wheel cylinders are in and the brake shoes are properly adjusted.So you can get to those now.By now, you know that I prefer the gravity bleed system,perhaps with an assistant now and then, on our old A-bodies.
Ok thats it for now
