349D2 MHPU Mobile Hydraulic Power Unit Hydraulic System Pump Control (Negative Flow) - Test Caterpillar

Specification

Note: Certain machines will default to "Economy Mode" at machine startup. Change to "High Hydraulic Power Mode" before performing the test procedure.

Illustration 1	g01516082
Pressure/Flow characteristic curve

Note: Specifications for flow rates are based on an engine speed of 1800 rpm. To get more accurate test results, measured flow should be corrected with the following calculation.

Flow measurements must be done in pressure rise.

Introduction

This test measures individual pump flow at the pump while a fixed negative flow control pressure is sent to the main pump regulator. Each pump is tested individually for an output flow rate at a specified delivery pressure and a specified negative flow control pressure.

The following procedures must be completed before performing the test procedure.

• Set the pilot pressure to the specifications in Testing and Adjusting, "Relief Valve (Pilot) - Test and Adjust" for the machine.

Required Tools

Illustration 2	g01623868
Tooling (B) 198-4240 Digital Pressure Indicator Gp

Illustration 3	g02535237
Tooling (C) 348-5430 Multi-Tool Gp

Illustration 4	g03775224
Flow meter tool layout (1) Drive pump (2) Delivery line (drive pump) (3) Idler pump (4) Delivery line (idler pump) (5) Swing motor (6) Makeup Line (swing motor) (7) Connector at swing motor

Illustration 5	g03775223
Tool setup (1) Drive pump (3) Idler pump (8) Negative flow control line (drive pump) (9) Negative flow control line (idler pump) (10) Elbow at negative flow port (11) Pressure tap (power shift pressure) (12) Idler pump regulator

Reference: Refer to Tool Operating Manual, NEHS1087 for operating instructions for the 348-5430 Multi-Tool Gp.

Note: Use Software License Card, NETG5049 with part number 348-5430 Multi-Tool Gp.

Machine Preparation

Drive Pump

Illustration 6	g03775215
Pump compartment (1) Drive pump (2) Delivery line (drive pump) (3) Idler pump (8) Negative flow control line (drive pump) (13) Pressure tap (drive pump delivery pressure)

1. Position the machine on level ground.

2. Stop the engine.

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

4. Attach 311-1362 Vacuum Cap onto the hydraulic tank. Attach an air supply hose onto the assembly. Apply 276 kPa to 414 kPa (40 psi to 60 psi). This procedure will pull a vacuum on the hydraulic system.

5. Install the following tools in accordance with the circuit diagram. Refer to Illustration 4.

   1. Disconnect delivery line (2) from drive pump (1).

   2. Install seal (D15), half flanges (D13), and blocking cover (D16) to the end of delivery line (2) by using bolts (D11) and washers (D12).

   3. Assemble and install seal (D15), adapter (D14), seals (D4), fitting (D10) and nipple assembly (D5) on drive pump (1) by using half flanges (D13), bolts (D11) and washers (D12).
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      Illustration 7	g03775221
      Swing motor (top view) (5) Swing motor (6) Makeup line (7) Connector (D19) Elbow (D20) Tee

   4. Disconnect makeup line (6) from connector (7) at swing motor (7).

   5. Assemble and install seals (D18), tee (D20), swivel elbow (D19), and coupling (D17) to connector (7) at swing motor (5).

   6. Install seal (D18) and makeup line (6) to tee (D20).

   7. Connect portable hydraulic tester (D1) and the test hoses between nipple assembly (D5) at drive pump (1) and coupling (D17) at swing motor (5).

   8. Connect 41368 kPa (6000 psi) pressure gauge (B2) to pressure tap (13) for drive pump delivery pressure.

   9. Install multi-tool group (C) on the engine to monitor engine speed.

   10. Install tooling (E) on negative flow control line (8) for drive pump (1). Refer to Illustration 5.

   11. Disconnect negative flow control line (8) from drive pump (1). Install seal (E2) and plug (E1) to the end of negative flow control line (8).

   12. Connect two tees (E3) to elbow (10) at the negative flow signal pressure port of drive pump (1). Install cap (E4) to tee (E3).

   13. Connect one end of test hose (E8) to tee (E3).

   14. Connect the other end of test hose (E8) to pressure tap (11) for the power shift pressure.

   15. Connect one end of test hose (E8) to tee (E3).

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

   17. Connect 3445 kPa (500 psi) pressure gauge (B2) to the other end of test hose (E8).

Idler Pump

Note: Perform the test for the drive pump and the test for the idler pump one at a time.

Illustration 8	g03775222
Pump compartment (1) Idler pump (3) Drive pump (4) Delivery line (idler pump) (9) Negative flow control line (idler pump) (14) Pressure tap (delivery pressure for the idler pump)

1. Position the machine on level ground.

2. Stop the engine.

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

4. Attach 311-1362 Vacuum Cap onto the hydraulic tank. Attach an air supply hose onto the assembly. Apply 276 kPa to 414 kPa (40 psi to 60 psi). This procedure will pull a vacuum on the hydraulic system.

5. Install the following tools in accordance with the circuit diagram. Refer to Illustration 4.

   1. Disconnect delivery line (4) from idler pump (3).

   2. Install seal (D15), half flanges (D13), and blocking cover (D16) to the end of delivery line (4) by using bolts (D11) and washers (D12).

   3. Assemble and install seal (D15), adapter (D14), seals (D4), fitting (D10) and nipple assembly (D5) on idler pump (3) by using half flanges (D13), bolts (D11) and washers (D12).
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      Illustration 9	g03775221
      Swing motor (top view) (5) Swing motor (6) Makeup line (7) Connector (D19) Elbow (D20) Tee

   4. Disconnect makeup line (6) from connector (7) at swing motor (5).

   5. Assemble and install seals (D18), tee (D20), swivel elbow (D19), and coupling (D17) to connector (7) at swing motor (5).

   6. Install seal (D18) and makeup line (6) to tee (D20).

   7. Connect portable hydraulic tester (D1) and the test hoses between nipple assembly (D5) at idler pump (3) and coupling (D17) at swing motor (5).

   8. Connect 41368 kPa (6000 psi) pressure gauge (B2) to pressure tap (14) for the delivery pressure of idler pump (3).

   9. Install multi-tool group (C) on the engine to monitor engine speed.

   10. Install tooling (E) on negative flow control line (9) for idler pump (3). Refer to Illustration 5.

   11. Disconnect negative flow control line (9) from idler pump (3). Install seal (E2) and plug (E1) to the end of negative flow control line (9).

   12. Connect two tees (E3) to the elbow at the negative flow signal pressure port of idler pump (3). Install cap (E4) to tee (E3).

   13. Connect one end of test hose (E8) to tee (E3).

   14. Connect the other end of test hose (E8) to pressure tap (11) for the power shift pressure.

   15. Connect one end of test hose (E8) to tee (E3).

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

   17. Connect 3445 kPa (500 psi) pressure gauge (B2) to the other end of test hose (E8).

Test Procedure

Note: Perform the test for the drive pump and the test for the idler pump one at a time.

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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. Increase the hydraulic oil temperature to 55° ± 5°C (131° ± 9°F).
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   Illustration 10	g03775219
   Monitor (A) Display (B) Keypad (C) Up key (D) Left key (E) Down key (F) Right key (G) Back key (H) Home key (J) OK key (K) Menu key

3. Start Service Mode and input a fixed power shift pressure of 2000 kPa (290 psi).

   1. Press menu key (K).

      Note: If more than 30 seconds pass between pushing the keys on the keypad, the menu mode will be canceled and the previous display will be restored to message display (A).

   2. Press right key (F) to highlight "SERVICE" menu option.

   3. After the "SERVICE" option is highlighted, press OK key (J).
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      Illustration 11	g01148206

   4. After OK key (J) is pressed, the screen in Illustration 11 will be displayed. The password for the service menu is "FFF2". The keys for direction are used to input the password. Press left key (D) or right key (F) to change the position of the flashing character. Press OK key (J) to enter the highlighted character.

   5. After entering the last letter of the password, the monitor will continue with the "SERVICE" screen.

   6. Repeatedly press down key (E) to highlight the "DEVICE TEST" line on the display.

   7. After the "DEVICE TEST" line is highlighted, press OK key (J).

   8. Once the "DEVICE TEST" screen is displayed, press down key (E) until "POWER SHIFT PRES" appears on the display.

   9. When "POWER SHIFT PRES" is highlighted, press OK key (J).

   10. Place the machine controls at the following settings: engine speed dial "10" and AEC switch OFF. Refer to Testing and Adjusting, "Engine Performance - Test (Engine Speed)" for engine rpm settings.

       Note: Press OK key (J) within 5 seconds after completion of Step 3.j to ensure high idle.

   11. The "POWER SHIFT PRES" will now be displayed. Line 4 of the display will now change to a numeric value. These characters represent the power shift pressure (kPa).

   12. Press left key (D) or right key (F) to increase or decrease the numeric value that is displayed on line 4 of the display. Pressing left key (D) decreases the power shift pressure. Pressing right key (F) increases the power shift pressure.

       Note: The value for power shift pressure on the monitor may not always match the pressure reading on the pressure gauge. Adjust the value on the monitor until the desired power shift pressure is attained on the pressure gauge that is connected to the pressure tap for power shift pressure. The actual power shift pressure must be 2000 kPa (290 psi) on the pressure gauge.

       Note: To prevent a change in power shift pressure during the main pump flow test, do not exit the "DEVICE TEST" screen and do not turn the engine start switch to the OFF position.

       Note: Refer to Systems Operation, "Monitoring System" for the machine for additional information on Service Mode.

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   Illustration 12	g03775220
   Portable hydraulic tester (flow meter) (D1) Portable hydraulic tester (flow meter) (15) Valve

4. Turn valve (15) on portable hydraulic tester (D1) clockwise until the pump delivery pressure is 6850 kPa (994 psi).

5. Record the negative flow rate in Table 1.