SHAFT AS 3666679 - Caterpillar

Illustration 1 g06293175Reference: For more information, refer to "308E2 CR Mini Hydraulic Excavator Margin Pressure - Test and Adjust" on Caterpillar Channel1.https://channel1.mediaspace.kaltura.com/media/308E2+CR+Mini+Hydraulic+Excavator+Margin+Pressure+-+Test+and+Adjust/0_ej2t06j3
Specification
Table 1
Margin Pressure
Machine Settings Engine Speed
Engine Speed Dial "High Idle"
Item Specification Actual
Margin pressure 1200 100 kPa (174 15 psi) Introduction
Margin pressure is the difference between the pump discharge pressure and the load sensing signal pressure. Use the following procedures to test or adjust the margin pressure.Required Tools
Illustration 2 g01879273
Tooling (D)
Table 2
Required Tooling
Tool Item Part Number Description Qty
D 1U-5796 Pressure Differential Tool Gp
D1 177-7861 Hose As (4.3 M (14 FT)) 2
D2 6V-4143 Quick Connect Coupler 4
D3 6V-3965 Fitting 3
D4 6V-4144 Quick Connect Coupler 1
D5 8T-0859 Pressure Gauge (0 TO 25,000-KPA (0 TO 3,600-PSI)) 1
D5 8T-0861 Pressure Gauge (0 TO 60,000-KPA (0 TO 8,700-PSI)) 1
D6 8C-8431 Tee 1
D7 1U-5793 Oil Filter Pressure Differential Gauge Gp 1
D8 6V-0484 Elbow 1 Reference: Refer to Special Instruction, SEHS8979, "Component Identification and Calibration of the 1U5796 Differential Pressure Gauge Group" for more information on using Tooling (D).Machine Preparation
Position the machine on level ground.
Stop the engine.
If equipped with "Power on Demand", uninstall "Power on Demand" using Cat ET.
If equipped with Eco mode, disable Eco mode using the monitor.
Release the pressure in the hydraulic system. Refer to Testing and Adjusting, "System Pressure-Release".
Illustration 3 g06098932
Main hydraulic pump
(1) Load sense pressure tap
(2) Pump discharge pressure tap
Attach tooling (D) to pressure taps (1) and (2).
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, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat® products.Dispose of all fluids according to local regulations and mandates.
Test Procedure
Start the engine.
Place the hydraulic activation control lever in the UNLOCKED position.
Increase the hydraulic oil temperature to 55° 5°C (131° 9°F).
Place the machine controls at the following settings: engine speed dial "High Idle".
Check the pressure reading for the differential pressure at tooling (D7).
The pressure reading on the differential pressure gauge should be 1200 100 kPa (174 15 psi). If the reading at pressure tap (1) is not within the specification, adjust the margin pressure.Adjustment Procedure
Illustration 4 g06098967
Margin pressure adjustment
(3) Lock nut
(4) Adjustment screw
Lower all implements to the ground.
While holding adjustment screw (4) with a hex wrench, loosen lock nut (3) with a combination wrench. Turn adjustment screw (4) counterclockwise to decrease the pressure setting and turn adjustment screw (4) clockwise to increase the setting.
When the pressure setting is adjusted, hold adjustment screw (4) with a hex wrench and tighten lock nut (3) to a torque of 21 2 N m (15 1 lb ft).