M313C, M315C, M316C, M318C and M322C Excavators and M318C and M322C Material Handlers Hydraulic System Caterpillar

The load sensing signal ensures that the main pump pressure does not overload the engine below full load rpm. The load sensing signal works with the margin stem in order to control the pump displacement. As system pressure rises, the load sensing signal will cause the main pump to destroke. This ensures that a constant load is placed on the engine.

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

Preparation

Show/hide table



Illustration 1	g01205986
The remote pressure taps are located behind the left rear access door. (1) Pressure tap (Load sensing signal pressure)

1. Connect a 60000 kPa (8700 psi) pressure gauge to pressure tap (1) .

2. Start the engine.

3. Adjust the engine speed to HIGH IDLE by turning the engine speed dial to position 10.

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

Test

Show/hide table



Illustration 2	g01259282
Soft Switch Panel (2) Power mode control

1. At the soft switch panel, select "Power Mode P" by pushing down on the button for power mode control (2). The second indicator light will illuminate when "Power Mode P" has been selected.

2. Lower the left console.

3. Slowly move the bucket control lever to the full BUCKET CLOSE position.

4. Check the load sensing signal pressure at pressure tap (1). Refer to Testing and Adjusting, "Specifications" in this manual for the correct load sensing signal pressure.

Adjust

Show/hide table



Illustration 3	g01259284
Main Control Valve ( M313C, M315C, and M316C) (3) Load sensing signal limiter valve

Show/hide table



Illustration 4	g01259286
Main Control Valve ( M318C, M318C MH, M322C, and M322C MH) (3) Load sensing signal limiter valve

1. To adjust the load sensing signal pressure, slowly move the bucket control lever to the full BUCKET CLOSE position.

2. Loosen the locknut on the adjustment screw for load sensing signal limiter valve (3) .

3. Turn the adjustment screw of load sensing signal limiter valve (3) until the pressure is set to the correct specification. Turn the adjustment screw clockwise in order to increase the load sensing signal pressure. Turn the adjustment screw counterclockwise in order to decrease the load sensing signal pressure.

   Note: A quarter turn of adjustment screw changes the pressure by approximately 4500 kPa (650 psi).

   Note: Always make the final pressure adjustments on the pressure rise.

4. Tighten the locknut.