WRENCH-ADJ.END 8F2243 - Caterpillar

Boom Functions
Illustration 3 g02160622
(14) Charge pressure main relief valve (15) Quick-drop pilot valve (16) Hook brake release pilot valve (17) Boom brake release pilot valve
Illustration 4 g02159819
(18) Boom motor flushing input line (19) Counter balance valve (20) Crossover relief and makeup valve for raising (21) Crossover relief and makeup valve for lowering (BML) Boom motor lower test port (22) Boom winch motor (23) Boom brake (BMR) Boom motor raise test port (24) Boom motor flushing output line (25) Boom raise (26) Boom winch loop flushing output (lower only) (27) Boom lowerThe following components are associated with the boom circuit: boom pilot control (2), boom kick-out solenoid (12), boom brake release pilot valve (17), boom counter balance valve (19) and crossover relief and makeup valves (20) and (21) .Boom Lower
If boom pilot control (2) is moved to the LOWER position, pilot oil will flow from the boom pilot control to the actuator piston in the control valve for the boom implement pump. This piston controls the angle of the pump swashplate. The implement pump will upstroke and send oil to the boom motor. The pressure will begin to increase in the boom lower (27) side of the winch motor. The increase in pressure will cause counterbalance valve (19) to open. When counterbalance valve (19) is opened, some oil is allowed to exit the winch loop through motor flushing valve (3). Also when counterbalance valve (19) is open, some oil is allowed to pass to the boom raise (25) side of the winch loop. The oil raises the pressure in the boom raise side of the winch loop. The rise in pressure occurs slightly before boom brake (23) releases. The pilot oil that is being sent to the pump actuator piston also flows to boom brake release pilot valve (17). When boom brake release pilot valve (17) is activated, the charge oil will release the winch brake and allow the boom to lower. Since the pressures are nearly equal on either side of boom winch motor (22) when boom brake (23) releases, the stresses on the internal components of the winch are reduced.Boom Raise
If boom pilot control (2) is moved to the RAISE position, pilot oil will flow from the boom pilot control to the actuator piston in the control valve for the boom implement pump. This piston controls the angle of the pump swashplate. The implement pump will upstroke and send oil to the boom motor. The pressure will begin to increase in the boom raise (25) side of the winch motor. The pilot oil that is being sent to the pump actuator piston also flows to boom brake release pilot valve (17). When boom brake release pilot valve (17) is activated, the charge oil will release winch brake (23) and allow the boom to raise.Boom Kickout Switch
The boom winch circuit also has a