Hi, I have a 1999 Peugeot Partner van with a brake problem. Over the last couple of days I've noticed the brake pedal become hard on several occasions. First time I noticed was when I set off from cold to do a 3 point turn and the pedal felt hard. Second time, i'd coasted a short distance in neutral and when I applied the brakes the pedal was hard. Third time, I was braking from about 40mph coming to a junction and the pedal gradually became harder. Sudden braking gives a normal pedal and good stopping power. Pedal feels fine if the engine has been revving a bit but seems to go hard at nearer tick over RPM...any ideas?