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System Operation
Normal Operation:
1. During truck operation, the lubrication cycle timer
(1, Figure 3-4) will energize the system at a preset
time interval.
2. The timer provides 24 VDC through the normally
closed relay, RB7K5 (4) 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 3-3)
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.
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).
1. Hydraulic Oil Return
2. Hydraulic Oil Supply
3. Pump Solenoid Valve
4. Pressure Reducing Valve
P3- 4
FIGURE 3-3. HYDRAULIC SCHEMATIC
5. Motor Pressure Gauge
6. Flow Control Valve
7. Hydraulic Motor
8. Grease Pump
Automatic Lubrication System
5. During this period, the injectors will meter the
appropriate amount of grease to each lubrication
point.
6. When grease pressure reaches the pressure
switch (3, Figure 3-4) setting, the switch contacts
will close and energize the relay RB7K5, remov-
ing power from the hydraulic motor/pump sole-
noid and the 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.
7. After the pump solenoid valve is de-energized,
hydraulic pressure in the manifold drops and the
vent valve 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.
8. The system will remain at rest until the lubrication
cycle timer turns on and initiates a new grease
cycle.
9. Pressure Switch (N.O.)
10. Check Valve
11. Vent Valve
12. Orifice
13. Injector Bank
P03018 4/00
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Table of Contents
Troubleshooting
