RING-PISTON- 2292868 - Caterpillar

Raise Position
Lower and float pilot pressure (27) is vented to tank. Raise pilot pressure (24) of 4100 200 kPa (595 29 psi) shifts stem (23) 15 mm (.590 in) to the left [towards pilot pressure port (27)]. This positions the stem (23) such that passages (31) and (30) are blocked from tank which allows the signal pressure in chambers (2) and (14) to become equal to the pressure at pump port (4) and (11). Pump signal oil flows from pump port (4) through orifice (9) to chamber (2) and from pump port (11) through orifice (20) to chamber (14). Signal pressure in chamber (2) closed unloading valve (8) preventing pump flow from pump port (4) to rear brake cooling port (3). Signal pressure in chamber (14) closes unloading valve (13) preventing flow from pump port (11) to rear brake cooling port (12). Pump port (4) flow of 490 liter/min (127 U.S. gpm) is now directed to passage (32) and then to the head