Left.4WD. Left.MEGA CAB. Right.4WD. Right.MEGA CAB. A Bushing, typically made of rubber, used to provide a surface for the Disc Brake Caliper guide pin to move freely. A rubber boot used to protect the Disc Brake Caliper guide pin from dirt, debris and moisture to prevent corrosion. Disc Brake Bushing. Disc Brake Caliper Bushing. Disc Brake Caliper Pin Seal. clip. cover. Guide Pin Seal. mount. outer. sleeve. Slide Pin Boot. Included with: Caliper.