Komatsu WA200-5H, WA200PT-5L, WA200-5L, WA200-5 Loader Service Manual

Table of Contents

01 GENERAL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 01-1
10 STRUCTURE AND FUNCTION. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-1
20 TESTING, ADJUSTING AND TROUBLESHOOTING . . . . . . . . . . . . . . . . . . . . . . . . . .20-1
30 DISASSEMBLY AND ASSEMBLY. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30-1
90 OTHER. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90-1

Manual Extract WHEN BALANCED:

● If the rear brake piston is filled with oil and the oil pressure between ports PA and A rises, the oil flowing through orifice c of spool (5) into chamber E pushes back spool (5) to the left against spring (4) and close ports PA and A from. Since port Ta is kept closed at this time, the oil which flowed into the brake piston is held and the brake is kept operated.

● At the time when spool (5) is pushed to the left, the front brake piston is filled with oil and the pressure between ports PB and B rises. As a result, the oil which flowed through orifice d of spool (6) into chamber F pushes back spool (6) to the left by the moving distance of spool (5) to close ports PB and B. Since port Tb is kept closed, the oil which flowed into the brake piston is held and the brake is kept operated.

● The oil pressure in the rear brake circuit (on port A side) is balanced with the pressing force of the brake pedal. The oil pressure in the front brake circuit (on port B side) is balanced with the oil pressure in the rear brake circuit (on port A side).

● If spools (5) and (6) move to the right stroke end, the passes between ports PA and A and between ports PB and B are fully open and the oil pressure in the rear and front brake circuits is equal to the oil pressure from the pump. Accordingly, the operator can adjust the braking force with the brake pedal until spool (5) and (6) move to the right stroke end.