326F Excavator Hydraulic System Caterpillar

Specification

Hydraulic Power Conversion

Illustration 1	g02729042
(6) Hose (boom cylinder rod end) (7) Hose (boom cylinder head end) (8) Hose (boom cylinder head end) (9) Hose (boom cylinder rod end)

Introduction

This test measures two pump flow to the boom cylinders at the boom foot. Both pumps are tested for output flow at specified pressures. If the results from this test are not within the specification, refer to Testing and Adjusting, "Main Pump (Flow) - Test (Constant Horsepower Flow Control)" in order to isolate any problem with the pumps.

Note: If the operational checks (cycle time) indicate that slow speed of an implement is common to the circuits of one pump, the problem is most likely in the hydraulic system. Then perform the pump flow tests. Refer to Testing and Adjusting, "Main Pump (Flow) - Test (Hydraulic Power)".

Preliminary Test

• Testing and Adjusting, "Relief Valve (Pilot) - Test and Adjust"

• Testing and Adjusting, "Relief Valve (Main) - Test and Adjust"

• Testing and Adjusting, "Solenoid Valve (Proportional Reducing) - Calibrate (Power Shift Pressure)"

• Testing and Adjusting, "Solenoid Valve (Proportional Reducing) - Calibrate (Negative Flow Control)"

Required Tools

Illustration 2	g02571852
Tooling (A) 198-4240 Digital Pressure Indicator Gp

Illustration 3	g02724455

Machine Preparation

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Illustration 4	g02280104

1. Position the machine on level ground in the service position. Refer to Illustration 4.

2. Stop the engine.

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

4. Attach 311-1362 Vacuum Cap onto the hydraulic tank. Attach an air supply hose onto the assembly. Apply 276 to 414 kPa (40 to 60 psi). This procedure will pull a vacuum on the hydraulic system.
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   Illustration 5	g03708902
   Pump compartment (1) Pressure tap (delivery pressure for drive pump) (2) Pressure tap (delivery pressure for idler pump) (3) Pressure tap (power shift pressure)

5. Connect 41,368 kPa (6,000 psi) pressure sensors to pressure tap (1) and pressure tap (2) for delivery pressure from both pumps.
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   Illustration 6	g03708903
   Flow meter tool layout at boom foot Tooling D (4) Connector (boom cylinder lines) (5) Boom cylinder (6) Line (boom cylinder rod end) (7) Line (boom cylinder head end) (8) Line (boom cylinder head end) (9) Line (boom cylinder rod end)

6. Install the following tools in accordance with the flow meter tool layout. Refer to Illustration 6.

   1. Disconnect line (8) and line (9) from boom cylinder (5).

   2. Install O-ring seal (D11) and plug (D12) to the end of line (8) and line (9).

   3. Install cap (D13) on connector (4) for the boom cylinder lines.

   4. Disconnect line (6) and line (7) from boom cylinder (5).

   5. Install cap (D13) on connector (4) for the boom cylinder lines.

   6. Install O-ring seal (D11), connector (D10), O-ring seal (D4), and coupler assembly (D5) to the end of line (6) and line (7).

   7. Remove 311-1362 Vacuum Cap and install the filler plug for the hydraulic tank.

   8. Connect portable hydraulic tester (D1) and the test hoses between coupler assembly (D5) on line (6) and coupler assembly (D5) on line (7).

      Note: In order to avoid damage to the flow meter, make sure that the direction of oil flow is correct. The proper direction of flow is from line (7) for the boom cylinder head end, through portable hydraulic tester (D1), and return through line (6) for the boom cylinder rod end.

Test Procedure

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To prevent personal injury or equipment damage from failure of the hydraulic test equipment or associated circuit components because of blocked pump flow, make sure that the test equipment valves are fully open before starting the engine.

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To prevent personal injury and/or equipment damage from failed lines or components while the hydraulic test equipment is returned to the open flow position, slowly open the hydraulic test equipment valve while monitoring the pump flow. If pump flow does not increase as the valve is opened, shut the engine off and determine what is preventing the pump from upstroking.

1. Start the engine.

2. Place the hydraulic activation control lever in the UNLOCKED position.

3. Place the machine controls at the following settings: engine speed dial "1" and AEC switch OFF.

4. Move the joystick for the boom to the full BOOM RAISE position. Hold the joystick for the boom in this position.

5. Slowly increase engine speed to speed dial "10".

6. Override fan speed to 850 rpm.

   1. Enter "Service" Menu.

   2. Enter password "9992".

   3. Select "Override Parameters".

   4. Override "Desired Fan Speed" to 850 ± 50 rpm or less.

7. Increase the hydraulic oil temperature to 55° ± 5°C (131° ± 9°F).
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   Illustration 7	g02599896
   Portable hydraulic tester (flow meter) (D1) Portable hydraulic tester (flow meter) (17) Valve

8. Turn valve (17) on portable hydraulic tester clockwise. Record the following items for each measuring point in Table 1.

   • Drive Pump Pressure

   • Idler Pump Pressure

   • Measured Flow

   Note: Flow measurements must be done only during pressure rise.

9. Return the joystick for the boom to the NEUTRAL position.

10. Stop the engine.

11. Calculate the hydraulic power using the average pump pressure and the measured flow. Refer to Table 2 for Metric (kW) and English (hp) calculations.

12. Let the hydraulic oil cool to 55° ± 5°C (131° ± 9°F) and repeat the test.

    Note: If second test results differ from the first test then run a third test.

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