ENGINE AR 1157641 - Caterpillar

Testing and Adjusting the Hydraulic Screed Counterbalance System
Do not operate or work on this machine unless you have read and understand the instructions and warnings in the Operation and Maintenance Manual. Failure to follow the instructions or heed the warnings could result in injury or death. Contact any Caterpillar dealer for replacement manuals. Proper care is your responsibility.
Introduction
The screed counterbalance system applies hydraulic pressure to the rod end of the screed lift cylinders. An essential result of the counterbalance system is the ability to reduce marks in the asphalt mat as the machine comes to a stop. There is also a reduction of wear on the screed plates. This is accomplished by transferring the weight of the screed to the machine. The following procedure will test the hydraulic screed counterbalance system. This test will ensure that the system is operating within an acceptable pressure range. The settings may vary and the settings are based on the desired application.Standard Tools
Illustration 1 g00924478
Gauge and CouplerThe following table provides a list of the tools that are used in order to perform the following test procedure. These tools are included with the hydraulic screed counterbalance system. The tools will remain in place after this procedure and during paving operations.
Table 1
Tools    
Tooling     Item     Part Number and Description     Quantity    
A     A1     8T-0855 Pressure Gauge
0 to 4000 kPa (0 to 580 psi)     1    
A2 207-4862 Adapter     1    Test Procedure
Perform the following procedure before you perform the test procedure that follows:
Park the machine on a level area that is clear from all equipment and material.
Verify that the service brake system and the parking brake system are in good working order.
Block the drive wheels in both directions.
Apply the parking brake.
Start the engine. Run the engine at high idle.
Clear all other personnel away from the machine.
Illustration 2 g00925234
Operator Station (1) Switch for the screed lift (2) Screed LOWER position
Set the switch for screed lift (1) to LOWER position (2). Lower the screed to the ground.
Illustration 3 g00925259
Main Console (3) Switch for the screed counterbalance (4) ON position
Set the switch for screed counterbalance (3) to ON position (4). This will supply power to the screed counterbalance system.
Illustration 4 g00925314
On/Off Valve for Screed Counterbalance The On/Off valve is located directly above the hydraulic tank on the left side of the machine. (5) On/Off valve (6) On/Off control knob
Observe the pressure gauge. The pressure reading should be 170 to 1400 kPa (25 to 200 psi). The desired pressure is dependent on the application and the environment of the paving operation. If the pressure is not within the prescribed limits, an adjustment needs to be made.Adjustment Procedure
Illustration 5 g00945448
The manifold valve for the screed counterbalance is located on the left side of the machine in the hydraulic tank compartment. (1) Manifold valve (screed counterbalance) (2) Locknut for adjustment knob (3) Adjustment knob
Loosen locknut (2) on manifold valve (1) .
Adjust the pressure of the screed counterbalance system with adjustment knob (3). Observe the