AFLS400

A couple of days ago while going through a drive thru I heard a light whistling noise coming from the driver's side engine bay by the brake booster. This whistling only occurs when you press the brakes. Once you release the brakes the noise goes away. I also disconnected the vacuum hose going from the brake booster check valve to the engine and the noise went away. Could I have a bad check valve, vacuum hose or brake booster. Has anyone experienced this issue and if so what was the fix for it?

dicer

It could be a vacuum leak some place. Since it happens when you apply the brakes its something to do with the booster. Hoses would leak all the time.

bjjPanda82

This happened to my mother inlaws 99 Camry a while back. In that case it was the booster itself. Changed it and the noise went away.
Hope that helps!

PureDrifter

iTrader: (10)

vacuum leak, either inside or around the brake booster.

AFLS400

Thanks everyone. I will likely replace the hose and check valve to see if that eliminates the noise. If not I guess the next step would be to replace the booster which looks like a pain to get to the bolts on the inside, under the dash.

AFLS400

Whistling problem solved. I replaced the paper thin gasket ($5 from dealer, part # 47275) between the brake master cylinder and the brake booster. It took about 10 minutes to remove and replace and the whistling noise is gone