etienne petit

My son bought a 2001 Mazda 626 es which sat for At least 5 years, I replaced fronts brake pads and rear shoes I also replaced the master cylinder for abs system now my problem is I only have around maybe half or less brake pedal. Rear brakes have no adjustment except when you back up and step on b rake pedal to adjust. Does anyone think that I need a new booster or have an suggestion to get a better brake pedal.

my son bought a 2001 mazda 626 es which sat for about 5 years , i replaced all brakes the problem is when you step on the brake pedal you might get half or less, i also replaced the master cylinder and it does have abs the rear does not adjust except when you back up then you have a good pedal does anyone think or have a clue do i need to replace booster?