Section 42 - Automatic Lubrication System OM4203 42-4 SYSTEM OPERATION 5. During this period, the injectors will meter the appropriate amount of grease to each lubrication point. Normal Operation: 1. During truck operation, the lubrication cycle timer (1, Figure 42-4) will energize the system at a pre- set time interval. 6. When grease pressure reaches the pressure switch (3, Figure 42-4) setting, the switch contacts will close and energize the relay RB6-K1, remov- ing power from the hydraulic motor/pump sole- noid and the pump will stop. The relay will remain energized until grease pressure drops and the pressure switch opens again or until the timer turns off. 2.
The timer provides 24 VDC through the normally closed relay, RB6-K1 (12) used to energize the pump solenoid valve (5), allowing hydraulic oil provided by the truck steering pump circuit to flow to the pump motor and initiate a pumping cycle. 3. The hydraulic oil pressure from the steering circuit is reduced to 325 to 350 psi (2 240 to 2 413 kPa) by the pressure reducing valve (4, Figure 42-3) before entering the motor. In addition, the amount of oil supplied to the pump is limited by the flow control valve (6). Pump pressure can be read using the gauge (5) mounted on the manifold. 7.
After the pump solenoid valve is de-energized, hydraulic pressure in the manifold drops and the vent valve (11, Figure 42-3) will open, releasing grease pressure in the lines to the injector banks. When this occurs, the injectors are then able to recharge for the next lubrication cycle. 4. With oil flowing into the hydraulic motor, the grease pump will operate, pumping grease from the reservoir to the injectors (13), through a check valve (10) and to the vent valve (11). 8. The system will remain at rest until the lubrication cycle timer turns on and initiates a new grease cycle. FIGURE 42-3. HYDRAULIC SCHEMATIC 1. Hydraulic Oil Return 2. Hydraulic Oil Supply 3. Pump Solenoid Valve 4.
Pressure Reducing Valve 5. Motor Pressure Gauge 6. Flow Control Valve 7. Hydraulic Motor 8. Grease Pump 9. Pressure Switch (N.O.) 10. Check Valve 11. Vent Valve 12. Orifice 13. Injector Bank