OM4203 Automatic Lubrication System - Section 42 42-3 SYSTEM COMPONENTS Vent Valve Filter With the vent valve ( 7, Figure 42-1) closed, the pump continues to operate until maximum grease pressure is achieved. As this occurs, the vent valve opens and allows the grease pressure to drop to 0, so the injectors can recharge for their next output cycle. A filter assembly (21, Figure 42-2) mounted on the grease reservoir filters the grease prior to refilling the reservoir from the shop supply. A bypass indicator alerts service personnel when the filter requires replacement.
Lubrication Cycle Timer Hydraulic Motor and Pump The solid state lubrication cycle timer (1, Figure 42-4) provides a 24 VDC timed-interval signal to energize the solenoid valve (5, Figure 42-1), providing oil flow to operate the grease pump motor. This timer is mounted in the Electrical Interface Cabinet. The rotary hydraulic pump (3 & 9, Figure 42-1) is a fully hydraulically operated grease pump. An integrated pump control manifold is incorporated with the motor to control input flow and pressure. Delay Timer Note: The pump crankcase oil level must be maintained to the level of the pipe plug port. If necessary, refill with 10W-30 motor oil.
The delay timer (7, Figure 42-4), located in the Electri- cal Interface Cabinet, provides a one minute delay in the low pressure warning lamp circuit to allow a nor- mally operating system to attain full grease system pressure without activating the warning lamp. If the system fails to reach 2000 psi (13 789 kPa) within this time period, the timer will apply 24VDC to several relays which will illuminate the low pressure warning lamp in the overhead display. An external 604K ohm resistor determines the delay period. Hydraulic oil supply inlet pressure must not exceed 3000 psi (20 685 kPa). Exceeding the rated pressure may result in damage to the system com- ponents and personal injury.
Pump Cutoff Pressure Switch (N.O. 2500 psi [17 237 kPa]) This pressure switch (18, Figure 42-2) de-energizes the pump solenoid relay when the grease line pressure reaches the switch pressure setting, turning off the motor and pump. Grease Reservoir The reservoir (12, Figure 42-1) has an approximate capacity of 90 lbs. (41 kg) of grease. When the grease supply is replenished by filling the system at the ser- vice center, the grease is passed through the filter to remove contaminants before it flows into the reservoir. Grease Pressure Failure Switch (N.O.
2000 psi [13 789 kPa]) Pressure Reducing Valve This pressure switch (24, Figure 42-2) monitors grease pressure in the injector bank on the rear axle housing. If the proper pressure is not sensed within 60 seconds (switch contacts do not close), several relays energize, actuating a warning lamp circuit to notify the operator a problem exists in the lube system. The pressure reducing valve (4, Figure 42-1), located on the manifold reduces the hydraulic supply pressure (from the truck steering circuit) to a suitable operating pressure, [325-350 psi (2 240-2 415 kPa)] for the hydraulic motor used to drive the lubricant pump.
Flow Control Valve Pressure Gauge The flow control valve (10, Figure 42-1) mounted on the manifold, controls the amount of oil flow to the hydraulic motor. The flow control valve has been fac- tory adjusted and the setting should not be dis- turbed. The pressure gauge (8, Figure 42-1) monitors hydrau- lic oil pressure to the inlet of the hydraulic motor. Injectors Each injector (23, Figure 42-2) delivers a controlled amount of pressurized lubricant to a designated lube point. Refer to Figure 42-2 for locations. Solenoid Valve The solenoid valve (5, Figure 42-1), when energized, allows oil to flow to the hydraulic motor.