STICK AS 2559728 - Caterpillar

Illustration 1 g03380699
Swing parking brake
(1) Port (pilot system oil)
(2) Swing parking brake solenoid valve
(3) Passage (pilot oil flow)
(4) Motor head
(5) Brake spring
(6) Passage (pilot oil flow)
(7) Piston chamber (brake piston)
(8) Brake piston
(9) Plate
(10) Friction plate
(11) Cylinder barrel
(12) Piston
(13) Body
(21) Temporary brake release screw Swing parking brake solenoid valve (2) is located on the left swing motor only. Both the left swing motor and the right swing motor are equipped with a swing parking brake. The operation of the swing parking brake is identical in both swing motors.The swing parking brake is located between motor head (4) of swing motor and body (13). The swing parking brake consists of the following components: brake spring (5), brake piston (8), plate (9), friction plate (10) and swing parking brake solenoid valve (2). Friction plate (10) is splined to cylinder barrel (11). Plate (9) is splined to body (13). Plate (9) and friction plate (10) move in an axial direction.Note: If the swing parking brake becomes inoperable due to failure of swing parking brake solenoid valve (2), the swing brake can be released by turning temporary brake release screw (21) in a clockwise direction until the temporary brake release screw stops.
Illustration 2 g03380704
Swing parking brake (disengaged position)
(1) Port (pilot system oil)
(2) Swing parking brake solenoid valve
(3) Passage (pilot oil flow)
(6) Passage (pilot oil flow)
(14) Spool
(15) Passage (pilot system oil)
(16) Spring
(17) Spool chamber
(18) Passage (drain) When the swing joystick, boom joystick, stick joystick and/or the bucket joystick is operated, swing parking brake solenoid valve (2) is energized by the machine ECM. Spool (14) shifts to the left against spring (16). Pilot oil in port (1) flows through passage (15), spool chamber (17), passage (3) and passage (6) to piston chamber (7). The pilot pressure shifts brake piston (8) to the left against brake spring (5). The force that holds plate (9) and friction plate (10) together is released. When the swing parking brakes are released, the swing operation of the upper structure is enabled.
Illustration 3 g02161050
Swing parking brake (engaged position)
(1) Port (pilot system oil)
(2) Swing parking brake solenoid valve
(3) Passage (pilot oil flow)
(6) Passage (pilot oil flow)
(14) Spool
(15) Passage (pilot system oil)
(16) Spring
(17) Spool chamber
(18) Passage (drain)
(19) Passage (drain) When the swing joystick is returned to the NEUTRAL position, swing pump supply oil to the swing motors is stopped. The machine ECM de-energizes the swing parking brake solenoid valve (2) in approximately 6.5 seconds after the swing joystick is returned to the NEUTRAL position. When the swing parking brake solenoid valve is de-energized, spool (14) is moved to the right by the force of spring (16). Spool (14) blocks pilot oil flow from port (1) to piston chamber (7). Brake spring (5) forces brake piston (8) to the right. The oil in piston chamber (7) flows through passage (3), spool chamber (17), and passage (19) of spool (14). The oil then flows through passage (18) to the case drain of the swing motors. As brake piston (8) moves to the right, plate (9) and friction plate