[squidtone]

I'm no expert, but I've messed with this brake system a bit.

The "hard as a rock" "pedal doesn't move" when the car is off is normal. It's downright scary how hard the pedal pressure has to be when the car is off.

It's possible you happen to need a brake booster rebuild, but it sounds to me that it's just a side issue. (by the way, if you need a brake booster rebuild, consider steve gregori rebuild/replating service...you get to keep your original booster so it will retain the original look...repop boosters have obvious differences....he'll rebuild it, replate it as long as it's in decent shape with no major rust.)

It sounds like your system still has air in it. It might be in the master, or in the calipers.

How are you bleeding your system? Did you bench bleed the master cylinder? Definitely have to do that, or you can use the bleeders on the side of the master.....using tubing looped into the reservoirs.

You have to press the "button" on the metering valve under the master when bleeding too....Otherwise I don't think you get proper fluid flow to the fronts.

The 4 piston calipers are infamous for needing seals every few years. They work fine when new, but an odd symptom of aging is they allow air to enter past the seals, while still keeping the fluid from leaking out. It gets almost impossible to bleed this way...you just can't get the air out of the calipers; air seeps in when you let up on the pedal during bleeding. To fix this, you might get lucky for some months with just gravity bleeding, but soon you must rebuild calipers.
This is assuming you have no pitting in the cast iron of the caliper bores. If there are pits, you may never get them to bleed correctly (air leakage). Do not despair, they can be sleeved with stainless...Inlinetube sells sleeved calipers. (actually, I think you can get new ones now too)

Dorman sells seal kits for the calipers, but they do not have the correct boots. Inlinetube sells rebuild kits, I'm not sure if they have the proper boots.

Good luck..