Hi, I have an R230 that today has started to emit a short squeal occasionally when braking. I tried braking when stationary with the engine running but in 'Park', and it still makes the noise as the pedal movement passes a certain point. If I hold it at the point where it squeals, it continues for about two seconds and then stops abruptly. Also, if I press the pedal a bit harder, there's a relay in the front of the dash that clicks once, coming off the brake and then going back on and it will click again. I'm thinking a vacuum leak that's being stopped by something, but with the relay as well, it's probably quite specific. Any ideas? Thanks.