Help is my master cylinder bad?

1994 honda accord ex

Problem: brakes iniital good, but then went all the way down, car did not stop

tried to fix: Bleeding the brakes, rear brake calipers were real rusty, tried to remove them but one of the bold in both sides was stripped so finally gave up.
Bleeded all 4 wheels, took out the fuse from the ABS

what happens now: brakes feel nice and tight, but once i drive the pedal goes to the floor directly, I'm not comfortable at all driving this way. Do you think its the master cylinder whch needs replacing?

If i replace the master cylinder do i have to bleed the wheels again (or just bench bleed the master cylinder). Please help, if i take it to a shop how much would they charge me excluding the cost of the master cylinder? (approx)

Was the brake fluid really dark? If so, then it may have been time to do the master cylinder.
Even with power assist, the pedal should not go more than half way down. If disk brakes all around, then can't be an adjustment problem.
So is either a master cylinder, or you have a very loose wheel bearing that is causing brake retraction from the wobble.

When you drive, you have power assist, and the brakes are going all the way down. When your car is OFF, there's no power assist, so it feels tight. You need to find the problem. Get a friend to assist you. You can't do it alone and do it right.