2) 2) SERVICE BRAKE OPERATED (OLD) SERVICE BRAKE OPERATED (OLD) FRONT 24 T1 P2 P1 A1 45 T2 A2 25 REAR 21 22 21 20 S2 S3 23 C3 G1 PS P B3 C4 C1 46 G2 23 PS T/M PARKING T2 Return line P 6 Return line D A B L S1 B A Main pump 955A4BS03 When the pedal of brake valve (24) 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 (20) enters the piston in the front and rear axles. Therefore, the service brake is applied. 4-5 S1 B1 T1 27 6 8