long brake pedal travel on start up

i have a 02 base rsx with automatic ive changed all brake parts up front except the abs pump the brake pedal sinks very far down and is sort of mooshy i can pump it up and it will sink straight down i can put the car in gear give full throttle and the brakes hold the car and abs does activate but sounds and feels weak

i have changed
rotors pads calipers hoses mastercylinder booster up front still the pedal sinks far on start up a friend thinks its the abs that has a internal leak more or less ending the pressure back to the mastercylinder like it does when abs activates on hard breaking

long brake pedal travel on start up