clutch slave cylinder problem on 1990 Chevrolet Camaro

well ive replaced my clutch slave 3 time already and everyone of them busted the seal under the boot. can anyone with experiance give me some ideas on what it could be

Asked by for the 1990 Chevrolet Camaro
What brand are you replacing the slave cyl with and how long does the cylinder last after installation? Are you sure your reservoir isn't contaminated with oil?