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| Illustration 1 | g01189384 |
Under Operator Platform (1) Cap (2) Hydraulic tank (3) Sight gauge (4) Return filter indicator | |
Hydraulic tank (2) is located under the operator platform.
The following systems share a common hydraulic tank:
- The propulsion hydraulic system
- The auxiliary hydraulic system
- The material feed hydraulic system
- The vibrator hydraulic system
- The 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 50 ± 20 kPa (7.3 ± 3 psi). The breather also limits the vacuum which can be created in the tank to a maximum of 2 ± .7 kPa (0.3 ± 0.1 psi).
Return oil flows into the tank through the return filter from the following components:
- The auxiliary control manifold
- The screed extension control valves
- The fumes motor return
- Truck hitch control valve
- The tow point control valve
The housing of the return filter contains filter indicator (4) and a bypass valve. The filter indicator shows whether the filter is plugged. The filter is plugged if the filter indicator is in the red zone while the engine is running at high idle, and the oil is at normal operating temperature. If the pressure differential across the filter is greater than 172 kPa (25 psi), the bypass valve opens and then return oil flows directly into the hydraulic tank.
The auxiliary pump draws oil from the tank through 150 micron suction screens which are located inside the tank.
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| Illustration 2 | g01189385 |
Front of Engine Compartment (5) Auxiliary pressure manifold | |
The auxiliary pump sends oil to auxiliary pressure manifold (5). This manifold is located inside the engine compartment, on the right side of the machine. The right hopper door provides access to this component.
The ports on auxiliary pressure manifold (5) are marked for identification. Pump supply oil enters the manifold through port "B". Port "C" of this manifold distributes oil to the truck hitch manifold. Port "D" of this manifold distributes oil to the tow point manifolds.
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| Illustration 3 | g01189386 |
Right Side of Machine (6) Hopper cylinder (7) Tow point cylinder (8) Bracket | |
Each side of the machine is equipped with hopper cylinder (6) and tow point cylinder (7) .
The hopper cylinders open and close the hopper wings. The hopper solenoids on the auxiliary manifold control the oil flow to the hopper cylinders. When oil is directed into the rod ends of the hopper cylinders, the hopper wings close. When oil is directed into the head ends of the hopper cylinders, the hopper wings open.
Each tow point cylinder raises and lowers the respective tow point. When the tow point is changed, the angle of attack of the screed is changed. The tow point solenoids on the tow point manifolds control the oil which flows to the tow point cylinders. When oil is directed into the head end of the tow point cylinder, the tow point lowers and the angle of attack then decreases. When oil is directed into the rod end of the tow point cylinder, the tow point rises and the angle of attack then increases.
Each side of the machine is equipped with a material thickness scale. This scale is located on bracket (8) near the tow point. The bracket can be rotated in order to provide the screed operator better visibility. When the angle of attack is changed, the tow point moves. Then the reading on the material thickness scale changes.
The operator can use the material thickness scale in order to determine the approximate mat thickness that is required for a given angle of attack. However, this scale has limitations. During operation, mat thickness should be checked periodically. Operators may need to make fine adjustments in order to accurately control the mat thickness.
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| Illustration 4 | g01189393 |
Rear of Machine (9) Screed hoist cylinder (10) Auger hoist cylinder | |
Each side of the machine is equipped with screed hoist cylinder (9) and equipped with auger hoist cylinder (10) .
Pressurized oil is directed into screed hoist cylinders (9) under the following conditions: the screed is lifted, or the screed counterbalance system is operating. The head ends of the screed hoist cylinders are always open to the hydraulic tank. When the screed is being lowered, the rod ends of the screed hoist cylinders are also open to the hydraulic tank. Gravity forces the screed to the ground. The inlet port at the rod end of each screed hoist cylinder contains an orifice. The orifice limits the rate at which the screed will lower.
When the auger lift switch is in the RAISE position, the auger raise solenoid directs oil into the rod end of the right auger hoist cylinder. Oil is transferred from the head end of the right auger hoist cylinder to the rod end of left auger hoist cylinder (10). The auger lower solenoid directs oil from the head end of the left auger hoist cylinder into the return passage in the auxiliary manifold.
When the auger lift switch is in the LOWER position, the auger lower solenoid directs oil into the head end of the left auger hoist cylinder. Oil is transferred from the rod end of the left cylinder to the head end of the right cylinder. The auger raise solenoid directs oil from the rod end of the right auger hoist cylinder into the return passage in the auxiliary manifold.