Hydraulic Tank
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| Illustration 1 | g01233607 |
Located Under the Operator Platform (1) Cap (2) Hydraulic tank (3) Sight gauge | |
Hydraulic tank (2) is located under the operator platform.
The following systems share a common hydraulic tank:
- Propel hydraulic system
- Auxiliary hydraulic system
- Material feed hydraulic system
- Vibrator hydraulic system
- Fan hydraulic system
Sight gauge (3) indicates the oil level in the tank. The capacity of the hydraulic tank is 152 L (40 US gal). Cap (1) for the hydraulic tank is equipped with a breather. The breather limits the maximum pressure in the tank to 34 kPa (5 psi). The breather also limits the vacuum which can be created in the tank to a maximum of 2 ± 0.7 kPa (0.3 ± 0.1 psi).
Hydraulic Filters
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| Illustration 2 | g01233609 |
Left Side of Machine (4) Pressure switch (5) Pressure tap (6) Charge filter (right) (7) Pressure tap (8) Pressure switch (9) Charge filter (left) | |
Right charge filter (6) and left charge filter (9) are located in the pump compartment, on the left side of the machine. The charge pumps direct oil through the charge filters. The base of each filter contains pressure switch (4) and (8). The Caterpillar Monitoring System uses the input from the pressure switches in order to operate the hydraulic filter plugged indicator.
The base of each charge filter also contains pressure tap (5) and (7). Charge pressure in the right and left propel systems can be measured at the pressure taps in the filter bases. When the machine is not moving, the charge pressure should be 2760 ± 170 kPa (400 ± 25 psi).
Oil Cooler Bypass Manifold
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| Illustration 3 | g01233610 |
Under the Operator Platform, Right Side of the Machine (10) Pressure Tap (11) Oil cooler bypass manifold | |
Case drain oil from the propel, vibratory, auger, and conveyor hydraulic systems is sent to oil cooler bypass manifold (11). The manifold is located under the operator platform, on the right side of the machine.
The ports of oil cooler bypass manifold (11) are marked for identification. Oil from the left propel motor case drain is directed into port "A" of the manifold. Oil from the right propel motor case drain is directed into port "D". Oil from the left propel pump case drain is directed into port "G".
Note: Oil from the right propel pump case drain is combined with case drain oil from the right and left feeder pumps. This combined oil is then sent directly to the hydraulic tank.
Port "H" of oil cooler bypass manifold (11) is equipped with pressure tap (10). Oil cooler inlet pressure can be measured at this tap.
The combined return oil from all of the hydraulic systems is sent out port "TC" to the oil cooler. The oil cooler is part of the cooling package (not shown, located to the right of the engine).
Oil cooler bypass manifold (11) is equipped with a 210 kPa (30 psi) check valve. When the pressure differential across the oil cooler is greater than the value of the check valve, the valve opens, and then oil is returned directly to the hydraulic tank.
Brake and Shift Solenoid
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| Illustration 4 | g01233612 |
Under the Operator Platform (12) Brake solenoid (13) Shift Solenoid | |
Brake solenoid (12) and shift solenoid (13) are located on the auxiliary manifold. The auxiliary manifold is located under the operator platform. The brake solenoid is the bottom right solenoid on the front face of the manifold. The shift solenoid is the bottom left solenoid on the front face of the manifold.
Note: Wire numbers and colors can be used in order to identify the brake solenoid and the shift solenoid. The 374-PK wire and the 277-BK wire are connected to the brake solenoid. The 334-BU wire and the 277-BK wire are connected to the shift solenoid.
The machine ECM controls brake solenoid (12) and shift solenoid (13). The brake solenoid must be energized in order to release the parking brakes. When the shift solenoid is energized, the machine operates in the travel speed range.
Brake Release Manifold
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| Illustration 5 | g01233614 |
Under the Operator Platform (14) Brake release manifold (15) Pressure tap (16) Hand pump (17) Needle valve | |
Brake release manifold (14) is mounted to the rear of the hydraulic tank, on the left side of the machine.
The manifold contains needle valve (17) and hand pump (16). When the needle valve is closed, the hand pump can be used to manually release the parking brakes.
The brake release pressure can be measured at pressure tap (15) in port "B" of the manifold.
Auxiliary Pressure Manifold
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| Illustration 6 | g01233619 |
Front of the Engine Compartment, Left Side (18) Auxiliary pressure manifold | |
Auxiliary pressure manifold (18) is mounted to the floor of the engine compartment. The left door at rear of the hopper provides access to this component.
The auxiliary pump provides flow to port "B" of auxiliary pressure manifold (18). Port "F" of this manifold directs oil to port "P" of the front wheel assist manifold.
Front wheel Assist Manifold
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| Illustration 7 | g01233620 |
Left Side of the Machine, Under the Hopper (19) Pressure tap (20) Front wheel assist solenoid (21) Pressure reducing valve (22) Front wheel assist manifold | |
Front wheel assist manifold (22) is located on the left side of the machine. This manifold is located under the left hopper wing, under a protective cover.
Front wheel assist manifold (22) contains front wheel assist solenoid (20), pressure reducing valve (21), two anticavitation check valves, a flow regulator, and a balance line. Port "P" of the front wheel assist manifold receives oil from port "F" of auxiliary pressure manifold (18). The pressure reducing valve limits the pressure which is available to the front wheel assist solenoid to 10342 kPa (1500 psi). The front wheel assist pressure can be measured at pressure tap (19) in the manifold.
Front wheel assist solenoid (20) controls the oil flow to the front wheel assist motors. When this solenoid is energized, the front wheel assist motors receive flow. The machine ECM controls this solenoid.
The machine ECM will energize the front wheel assist solenoid if the following conditions are met:
- The front wheel assist switch is in the ON position.
- Brake solenoid (12) is energized (brake is released).
- The propel lever is in the forward range.
- The propel speed dial is in the MINIMUM position.
- The decelerator pedal is not depressed.
- The propel mode switch is in the PAVE position or in the MANEUVER position.
The flow regulator ensures that an equal flow volume of 24 L/min (6 US gpm) is sent to each front wheel assist motor. The balance line equalizes the pressure in the lines to the front wheel assist motors. The anticavitation check valves prevent motor cavitation.