M318C Excavator Hydraulic System Caterpillar

The stick lowering control valve is a lock check valve that prevents stick drift. The stick lowering control valve is mounted on the stick cylinders.

Table 1

Required Tools
Part Number	Part Description	Qty
8T-0861	Pressure Gauge	1
6V-3014	Hose	1
6V-3989	Unvalved Nipple	1
6V-4143	Coupler Assembly	2

1. Release the pressure in the hydraulic system. Refer to Testing and Adjusting, "Hydraulic System Pressure - Release".

Show/hide table

NOTICE
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 Tools and Shop Products Guide" for tools and supplies suitable to collect and contain fluids on Caterpillar products. Dispose of all fluids according to local regulations and mandates.

Show/hide table



Illustration 1	g00917698
The pressure tap is located behind the left rear access door. (1) Main pump pressure

2. Connect a 60000 kPa (8600 psi) pressure gauge to pressure tap (1) .

3. Start the engine.

4. Place the engine speed dial in position 10.

5. Turn the signal limiter valve inward until the valve contacts the stop.

6. Increase the main relief valve pressure to a maximum of 42500 kPa (6165 psi). Refer to Testing and Adjusting, "Relief Valve (Main) - Test and Adjust".

Show/hide table



Illustration 2	g00842733
Main control valve (2) Stick relief valve (rod end)

7. Increase the stick relief valve (rod end) (2) to a maximum of 42500 kPa (6165 psi).

Test

1. Move the joystick to the full STICK OUT position until the stick cylinder is fully retracted.

2. While the joystick is in the full STICK OUT position, check the pressure at pressure tap (1). Refer to Testing and Adjusting, "Specifications" in this manual for the correct pressure.

Adjust

Illustration 3	g00842737
(3) Adjustment screw for stick lowering control valve

1. If the stick lowering control pressure is incorrect, turn the adjustment screw (3) in order to adjust the stick lowering control valve.

2. Adjust the stick relief valve (rod end) to the original setting. Refer to Testing and Adjusting, "Main Control Valve - Adjust (Implement Control Spools)".

3. Adjust the main relief valve to the original setting. Refer to Testing and Adjusting, "Relief Valve (Main) - Test and Adjust".

4. Adjust the signal limiter valve to the original setting. Refer to Testing and Adjusting, "Relief Valve (Signal Limiter) - Test and Adjust".