Komatsu PC500LC-10R Shop Manual page 327

10 STRUCTURE AND FUNCTION
1.
The pressurized oil from the self-pressure reducing valve
flows into brake chamber (a) through port (B).
2.
The pressurized oil in chamber (a) compresses brake
spring (1), and the brake piston (7) is moved upward.
3.
The disc (5) and plate (6) are separated. Accordingly, the
swing parking brake is canceled.
PC500LC-10R
COMPONENT PARTS OF SWING SYSTEM
10-233