Volvo xc90 uses "drum in hat" parking brake design for rear wheels of vehicle. whether engaged or not, the friction (lining) material for the parking brake can separate catastrophically from the shoe and lodge against the inside of the drum, causing one or both of the rear wheels to lock up, driveline damage, loss of control of the vehicle and/or braking component damage. upon inquiry to dealer (secor volvo of new london, connecticut), this problem is known to dealer and/or volvo. *tr