Weird Brakes...
 

89 GTU w/ TII front calipers.

They grab decently hard but when i press the pedal there is no feedback (supersoft pedal)

other times i can push them as hard as i can and the car will barely stop.

Any suggestions??
Any questions??

you swapped out the master cylinder and booster, didn't you?

i had all sorts of weird problems with a bad booster before. try swapping another one on

The problems with bad boosters, or bad booster lines if you have a turbo, is that they can be intermitant. So, as was already said, swap it out with a known good one and see if the problem goes away. Be advised though, there is a difference in size between the 4/5 lug and the turbo line has a one way valve in it.

i swapped the one that was on the car that just caused weak brakes w/ an s4 booster that was still "good" made the brakes better but nowhere near the way they should be.

so its narrowed down to booster?? booster and master cylinder?? it could it be a leak in the line that powers the booster? Just clarifying

It could be that you have to adjust the rod that goes into the booster.

Adjusting that rod wouldn't correct an intermitant problem. It's something else.

Swap the booster to a known good one so it can be crossed off the list. Then it's down to Master (which I don't think it is) or a bad one way valve.

Are we talking a turbo car here?

n/a car TII calipers

Actually it will, I had this issue after I swapped in my 929 booster and master, it would intermittently drag and cause the brakes fade like a mofo, I adjusted it so it was shorter and I no longer have an issue with brake fade.