I have a Citroen dispatch van 05 plate with the 1.9 Diesel engine .my brakes almost all of the time are fine and work well. However on occasions I have applied the foot brake and the pedal feels very hard and the braking is ineffective ...then moments later they are back to normal. The van had new brake shoes fitted to the rear brakes about 3 months ago....could this have any thing to do with the problem.
sounds like you have a servo fault. you need to check for vacuum at the pipe that fits in servo. if ok check/listen for vacuum leaking when brake pedal depressed slowly.if you can hear a leak then it points to servo faulty. this seems a common fault.
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