OER Parts offers a wide selection of Brake Components for your 1978 GMC Jimmy. OER Parts offers 1978 GMC Jimmy Wheel Cylinders, 1978 GMC Jimmy Front Wheel Cylinders 1978 GMC Jimmy Rear Wheel Cylinders, 1978 GMC Jimmy Wheel Cylinder Retainer, 1978 GMC Jimmy Drum Brake Bleeder Screws, 1978 GMC Jimmy Front Wheel Cylinder Repair Set, 1978 GMC Jimmy Rear Wheel Cylinder Repair Set, and 1978 GMC Jimmy Wheel Cylinder Pins.