TUBE AS 2573050 - Caterpillar

Introduction
The pressure reducing valve for the pilot circuit reduces the pump pressure to a controllable level for the pilot control valves. The pressure reducing valve is located below the floorplate in the operator's compartment on the boom and the hook control valve. Perform the following procedure to ensure that the pressure reducing valve for the pilot circuit is set accurately.
Illustration 1 g00489571
Location of the pressure reducing valve (pilot circuit)Required Tools
Illustration 2 g01089423
Tooling (A)
Illustration 3 g01089425
Tooling (B) ( 6V-7830 Pressure Gauge (Tetragauge))
Table 1
Required Tools    
Tooling    Item    Part
Number    Description    Qty    
A     A1     8T-0852     Pressure Gauge
40000 kPa (5800 psi)     1    
A2 6V-3989     Fitting     1    
A3 6V-4143     Coupler     2    
A4 177-7861     Hose As
41370 kPa (6000 psi)     1    
B     B1     8T-0862     Pressure Gauge
500 kPa (72 psi)     1    
B2 8T-0860     Pressure Gauge
40000 kPa (5800 psi)     1    
B3 8T-0855     Pressure Gauge
4000 kPa (580 psi)     1    
B4 6V-3081     Hose As
41500 kPa (6020 psi)     1    
B5 4S-6399     Connector     1    
B6 6V-4144     Coupler     1    
C     C1     6V-9507     Plug     1    
C2 4J-5477     O-Ring Seal     1    
C3 6V-9828     Cap As     1    Test Procedure
Move the machine to a smooth horizontal location. Move away from working machines and personnel.
Allow only one operator on the machine. Keep all other personnel away from the machine or in the view of the operator.
Engage the parking brake.
Fully retract the counterweight.
Stop the engine.
Remove the floorplate.
Illustration 4 g01308004
Connect tooling (A or B) to the pilot pressure port (TP3) .
Start the engine. Warm the hydraulic oil to a temperature of 65° 3°C (149 ° 5 °F).
Operate the engine at HIGH IDLE.
Move the hook control to the LOWER position.
Check the pressure at tooling (A or B). The pressure at tooling (A or B) should be 5200 70 kPa (750 10 psi).
If the pressure at tooling (A or B) is not within the specified limits, perform the following adjustment procedure.Adjustment Procedure
Illustration 5 g01308011
Pressure reducing valve (pilot circuit) (1) Adjustment screw (2) Locknut
Hold adjustment screw (1) and loosen locknut (2). Turn adjustment screw (1) counterclockwise in order to decrease the pressure setting. Turn adjustment screw (1) clockwise in order to increase the pressure setting. One full turn is approximately equal to 6000 kPa (870 psi).
When the pressure setting is adjusted, hold adjustment screw (1) with the hex wrench and tighten locknut (2) .
Repeat the test procedure. Make sure that the pressure is 5200 70 kPa (750 10 psi).