VALVE AS 2107291 - Caterpillar

Personal injury can result from hydraulic oil pressure and hot oil.Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system.Make sure all of the work tools have been lowered to the ground, and the oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand.
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids.Refer to Special Publication, NENG2500, "Caterpillar Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Caterpillar products.Dispose of all fluids according to local regulations and mandates.
Machine Preparation
Start the engine.
Lower the left console.
Position the machine on level ground.
Stop the engine.
Release the pressure in the hydraulic system. Refer to Testing and Adjusting, "Hydraulic System Pressure - Release".
Illustration 1 g01206011
The remote pressure taps are located behind the left rear access door. (1) Pressure tap (Main pump pressure)
Connect a 60000 kPa (8700 psi) pressure gauge to pressure tap (1) .
Illustration 2 g01216327
Main Control Valve (2) Hose (3) Tee
Remove the "LS" line at the "MLS" port on the main control valve.
Install an O-Ring seal onto the fitting at the "MLS" port on the main control valve.
Connect tee (3) at the "MLS" port on the main control valve.
Route hose (2) from tee (3) into the hydraulic tank.Note: Now, both the main control valve and "LS" lines of the main hydraulic pump are drained at the same time.
Start the engine.
Lower the left console.
Increase the hydraulic oil temperature to 55° 5°C (131° 9°F).
Illustration 3 g01216379
Soft Switch Panel (4) Automatic Engine Speed Control (AEC) (5) Hydraulic Modulation Control
At the soft switch panel, disable AEC (4) by pushing down on the button. The indicator light will not be illuminated when the AEC is disabled.
Illustration 4 g01215702
Right Joystick (5) Switch (hydraulic modulation)
Disable hydraulic modulation control (5). Press front switch (6) on the right joystick in order to deactivate the soft panel switch for hydraulic modulation. None of the indicator lights will be illuminated.Test
Adjust the engine speed to HIGH IDLE by turning the engine speed dial to position 10.Note: Do not activate any implements.At this time, the main pump output flow should be minimum. Minimum pump flow is determined by the position of the swashplate as the swashplate contacts the minimum displacement adjustment screw. The "LS" chambers in the main valve and in the main pump are drained to the hydraulic tank. The spool in the unloading valve should be in the open position.
Illustration 5 g01215818
Main Pump (12) Cap (Minimum displacement adjustment screw)
Check the main pump pressure on pressure gauge (1). The pressure gauge reading should be approximately 2800 to 3400 kPa (406 to 493 psi).If