Brake issues...

[amdeman]

Unusual situation with the brakes on an NZ new 1995 AE101 Corolla with ABS.

The brakes work (averagely), that is easy enough to compensate for, though when sitting (engine running) the brake pedal fades to the floor (with slight pressure) the brakes still on enough to hold the car from moving.

So far, to try and alleviate the issue, have replaced the brake master cylinder (new aftermarket one), the fluid, the front pads, flushed the entire system repeatedly, even reset the rear drums and handbrake.

Checked the vacuum, when unplugging the air hoses there is HEAPS (LOUD hissing noise once pulled off the booster).

How often do the one-way-valves on the vacuum side of things give out?

HELP!

Any ideas / suggestions as to what is going on?

All help greatly appreciated.

[CXGPWR]

If you have replaced the master cylinder., i believe the problem will be in your abs unit

[amdeman]

If you have replaced the master cylinder., i believe the problem will be in your abs unit

Any idea as to what it could be?
Say an issue with an air-lock (the easy, and cheap option)?

[CXGPWR]

I wouldnt have thought so, i would be pointing the finger at the valve assembily in the abs unit itself, the not so cheap option.

[amdeman]

I wouldnt have thought so, i would be pointing the finger at the valve assembily in the abs unit itself, the not so cheap option.

Or Pick a part?

Must be an ABS unit there amongst the yards...