Weird Servo Noises

[Justin S]

Car seems fine but the wife drove yesterday afternoon and it sounded like Darth Vader under the dash when she took her foot off the brake. I tried it when I got home from work and did the same. Noise was definately eminating from the servo area under the bonnet and under the dash. So went to see my mate, who is a mechanic and did it for a mile and then stopped and not done it since. Weird I know, but is there something other than the servo that has caused this. We checked all the servo hose and fittings at the garage last night and was silent and sound. I always thought that if the servo bellow split , it would affect the idle and the brake pedal, but it seemeed fine during the noisy times. Any ideas would be great.Cheers