M313C, M315C, M316C, M318C and M322C Excavators and M318C and M322C Material Handlers 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 (0 to 60,000 kPa (0 to 8,700 psi))	1
6V-3989	Fitting (TEST)	1
6V-4143	Quick Connect Coupler	2
6V-3014	Hose As	1

Note: Two technicians are required for this test.

Note: Prior to any adjustment, refer to the "Preparations" section in Testing and Adjusting, "Operational Checks".

Note: Prior to performing this test, the Testing and Adjusting, "Relief Valve (Pilot) - Test and Adjust" must be performed.

Preparation

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

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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 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.

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Illustration 1	g01205997
The remote pressure taps are located behind the left rear access door. (1) Pressure tap (Main pump pressure) (2) Pressure tap (Load sensing signal pressure)

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Illustration 2	g01253772
Main Control Valve ( M313C, M315C, and M316C) (3) Main relief valve (4) Load sensing signal limiter valve

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Illustration 3	g01205998
Main Control Valve ( M318C, M318C MH, M322C, and M322C MH) (3) Main relief valve (4) Load sensing signal limiter valve

2. Connect 60000 kPa (8700 psi) pressure gauges to pressure taps (1) and (2) .

3. Loosen the locknut on load sensing signal limiter valve (4). Turn the adjustment screw on the load sensing signal limiter valve clockwise until the adjustment screw contacts the stop.

   Note: Do not overtighten the adjustment screw.

4. Start the engine.

5. Adjust the engine speed to position 5 by turning the engine speed dial.

6. Increase the hydraulic oil temperature to 55° ± 5°C (131° ± 9°F).

7. Move the left joystick to the full STICK OUT position.

   Note: Stall the stick in the STICK OUT position.

8. Check the pressure reading at pressure tap (2). Loosen the locknut on main relief valve (3). Increase the main relief valve pressure by slowly turning the adjustment screw on the main relief valve clockwise. Continue turning the adjustment screw clockwise until the pressure at pressure tap (2) stops increasing.

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Illustration 4	g01206602
Main Control Valve (5) Stick relief valve (Rod end)

9. Increase stick relief valve (5) 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 (2). Refer to Testing and Adjusting, "Specifications" in this manual for the correct pressure.

Adjust

Illustration 5	g01250695
(6) Adjustment screw (Stick lowering control valve)

1. If the stick lowering control pressure is incorrect, turn adjustment screw (6) 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, "Relief Valve (Line) - Adjust (Implement)".

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".