2) 2) SERVICE BRAKE OPERATED SERVICE BRAKE OPERATED 19 Front P1 T1 A1 20 40 P2 T2 A2 16 17 16 Rear S2 B2 B1 S1 S3 18 G1 PS Parking Return line B3 41 T/M 18 18 PS G2 PS 22 23 24 2 29 30 D P A A Return line 21 25 B T B B Main pump L S 7609A4BS03 When the pedal of brake valve (19) is depressed, the operating force overcomes the force of the spring, and is transmitted to the spool. When the spool moves down, the inlet port is opened, and at the same time the hydraulic oil controlled the pressure level by the cut-off valve (15) enters the piston in the front and rear axles. Therefore, the service brake is applied. 4-5 PS 26 26