Brake master cylinder disco 2

Hi i recently changed the brake master cylinder on my disco 2 td5 bled the brakes according to the manual got a good pedal road tested the vehicle all seemed ok went out the following day and the brakes came on by them selves brake pedal was solid .the brakes came on gradually . Drove the car off the road waited a minute or two checked fluid all ok ihen fault cleared used the vehicle next day and same fault occured twice any ideas ?

aye i know exactly what it is , rod in servo that pushes master cylinder piston is too long , it has an adjustable end cap but its quite stiff to turn so rod needs holding with mole grips or good pliers whilst its adjusted clockwise to shorten , rod can be pulled out and refitted but its help by a star washer and can take a bit of fiddling and 3 hands to re-clip in, trail and errotr to get right but pedal will feel like it has slightly too much travel when correct

Thanks james will try tomorrow

Thanks james