Description:Piston part # 623-3030 for the parking brake that provides a method of stopping or holding the machine on grade. Parking brakes are automatically applied when the service brakes fail.Cat drive train brake components must endure incredible torque and high impact loads during a braking application. Cat designs and manufactures its brake components with these demands in mind. The result is a drive train brake system that lasts longer and works harder over the life of the machine.Attributes:• Cast iron piston• Outside Diameter: 101.37 mm (3.99 in)• Width: 70 mm (2.76 in)Application:Brake pistons are used in Cat drive train braking systems. Consult your owner's manual or contact your local Cat Dealer for more information.