1) 1) SERVICE BRAKE RELEASED SERVICE BRAKE RELEASED 19 Front P1 A1 P2 T1 20 40 T2 A2 Rear 16 17 16 S2 B2 B1 S1 S3 G1 18 PS B3 Parking T/M Return line 18 18 PS G2 PS 41 22 23 24 2 29 P 30 A A D Return line 25 T B B 21 B Main pump L S 7609A4BS02 When the pedal of brake valve (19) is released, the operating force is eliminated by the force of the spring, and the spool is returned. When the spool removes up, the drain port is opened and the hydraulic oil in the piston of axles return to the tank (21). Therefore, the service brake is kept released. 4-4 PS 26 26