[Model flyer]

Does the brake caliper carrier move freely on its sliders ? This allows the caliper to align with the pad and disc .If it stiff or stuck this can cause the problem you describe as it springs the caliper and piston back after the pedal is released causing the excessive pedal travel to take up the slack. Haveing the car cleaned by so called " hand car washes" that use pressure washer can cause the problem . Check all parts are clean ,lubricated and move freely . Any run out of disc or wheel bearing play can also cause this problem. Some pads can take what seems like an age to bed in so if all is well and your sure there's no air in system ( bleed all of the system not just the front this may take two or three circuits of the car ) then give pads time to bed and braking should improve.