While I was attempting to park my jeep across the street from my grandson's school to pick him up at 3:18, as I proceeded to pull in front of the apron so I could backup to a parking spot. In the process of going forward before I got a chance to put the jeep in reverse my brakes failed, hitting a parked car in front of me. I had my jeep towed to Old Center Island Auto Service. The mechanic removed a defective power brake booster and replaced it with a new one.