Hatch back brake problem

Well ive tried everything i can think of but its still to low for my liking!
1. Backed off the handbrake cable and adjusted the rear brakes up and pumped pedal and adjusted them up a little more.
2. Adusted the handbrake up and it works great now.
3. Adjusted the front wheel bearings.
The only thing i can think of now is to change the brake fluid and flush the system,any more ideas??
Thanks Baz

Try the pushrod from booster to master cylinder its adjustable, but if you over adjust your brakes will stay on.

Cheers ill give it a go 2 morro
Baz