Jens, Thanks for the advice. Sound continues even after looosing the power steering belt. Sound definetly comes from the black vacuum motor on left strut. Wondering which fluid is flowing through this pump. Noticed that I'm leaking dime size amount of brake fluid from brake master cylinder per day, but the fluid level in reserve doesn't go down. So, is this vacuum pump part of the braking system? Going to rebuilt/replace master cylinder to stop leak, hopefully this will end sound. Thanks, Glen P.S. I'll be offline til Tuesday