349D2 MHPU Mobile Hydraulic Power Unit Hydraulic System Main Pump (Flow) - Test - Constant Horsepower Flow Control 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	g06014330
P-Q characteristic curve

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

Note: Specifications for output flow rates are based on a power shift pressure at the pump of 2700 kPa (390 psi). The output flow rate changes approximately 5.2 L/min (1.4 US gpm) for each 100 kPa (14 psi) of power shift pressure in the higher range of the constant horsepower control.

Note: If the output flow rate of the pump is not within the specification, disconnect the negative flow control line from the pump that is being tested and perform the test again.

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

Introduction

This test measures individual pump flow at the pump. Each pump is tested individually for output flow at specified pressures. The pump that is not being tested is not under load and the pump remains at low-pressure standby.

Illustration 2	g01721640
(A) Message display (B) Monitor

Illustration 3	g03413181
The electronic control module is located in the compartment behind the cab. (C) Alarm lamp (D) Electronic control module

Note: Before starting main pump flow tests, check display (A) on monitor (B) and alarm lamp (C) on electronic control module (D) for normal operation. Lamp (C) should be green. If no faults are present, perform the operational checks. Refer to Testing and Adjusting, "Operational Checks".

Note: If the operational checks 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 (Constant Horsepower Flow Control)".

Note: If the operational checks indicate that slow speed of an implement is common to both pump circuits, the problem may be in the engine, the fuel, or the working altitude.

Note: Perform the following procedures before testing the main pump flow.

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

• Set the main relief valve to specifications. Refer to Testing and Adjusting, "Relief Valve (Main) - Test and Adjust" for the machine.

Required Tools

Illustration 4	g01623868
Tooling (B) 198-4240 Digital Pressure Indicator Gp

Illustration 5	g02535237
Tooling (C) 348-5430 Multi-Tool Gp

Illustration 6	g03413179
Tooling (D) (Flow meter tool layout)

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

Illustration 7	g03413176
Flow meter tool layout Tooling (D) ( 1) Swing motor (2) Connector at swing motor (4) Makeup line (swing motor) (6) Negative flow control line (drive pump) (11) Delivery line (idler pump) (12) Delivery line (drive pump) (13) Negative flow control line (idler pump) (23) Drive pump (24) Idler pump

Illustration 8	g03413177
Circuit diagram (1) Swing motor (2) Connector (4) Makeup line (swing motor) (5) Main control valve (8) Pressure tap (delivery pressure for idler pump) (9) Pressure Sensor (11) Delivery line for idler pump (12) Delivery line from drive pump (16) Pressure tap (delivery pressure for drive pump) (20) Pressure Sensor (21) Engine (23) Drive pump (24) Idler pump (50) Pressure tap (power shift pressure) (C1) Multitach (D1) 4C-9910 Portable Hydraulic Tester (Flow meter) (D16) 9U-7335 Blocking Cover (D19) Elbow (D20) Tee

Drive Pump

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

Illustration 9	g01241832
Pump compartment (8) Pressure tap (delivery pressure for idler pump) (12) Delivery line for drive pump (16) Pressure tap (delivery pressure for drive pump) (23) Drive pump (24) Idler pump (50) Pressure tap (power shift 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 flow meter tool layout and the circuit diagram. Refer to Illustration 7 and Illustration 8.

   1. Disconnect delivery line (12) from drive pump (23).

   2. Install seal (D15), half flanges (D13), and blocking cover (D16) to the end of delivery line (12) 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 (23) by using half flanges (D13), bolts (D11) and washers (D12).
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      Illustration 10	g03413180
      Swing motor (top view) (1) Swing motor (2) Connector (4) Makeup line (D19) Elbow (D20) Tee

   4. Disconnect makeup line (4) from connector (2) at swing motor (1).

   5. Assemble and install seals (D18), tee (D20), swivel elbow (D19) and coupling (D17) to connector (2) at swing motor (1).

   6. Install seal (D18) and makeup line (4) to tee (D20).

   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 nipple assembly (D5) at drive pump (23) and coupling (D17) at the swing motor.

   9. Connect 3447 kPa (500 psi) pressure sensor to tap (50) for power shift pressure. Connect 41368 kPa (6000 psi) pressure sensor to tap (16) for drive pump delivery pressure.

   10. Install multitach group (C1) on engine (21). This group is used to monitor engine speed.

Idler Pump

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

Illustration 11	g01241834
Pump compartment (8) Pressure tap (delivery pressure for idler pump) (11) Delivery line for idler pump (16) Pressure tap (delivery pressure for drive pump) (23) Drive pump (24) Idler pump (50) Pressure tap (power shift 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 flow meter tool layout and the circuit diagram. Refer to Illustration 7 and Illustration 8.

   1. Disconnect delivery line (11) from idler pump (24).

   2. Install seal (D15), half flanges (D13), and blocking cover (D16) to the end of delivery line (11) 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 (24) by using half flanges (D13), bolts (D11) and washers (D12).
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      Illustration 12	g03413180
      Swing motor (top view) (1) Swing motor (2) Connector (3) Tee (4) Makeup line (40) Elbow

   4. Disconnect makeup line (4) from connector (2) at swing motor (1).

   5. Assemble and install seals (D18), tee (D20), swivel elbow (D19) and coupling (D17) to connector (2) at swing motor (1).

   6. Install seal (D18) and makeup line (4) to tee (D20).

   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 nipple assembly (D5) at drive pump (23) and coupling (D17) at the swing motor.

   9. Connect 3447 kPa (500 psi) pressure sensor to pressure tap (50) for power shift pressure. Connect 41368 kPa (6000 psi) pressure sensor to pressure tap (8) for the delivery pressure of the idler pump.

   10. Install multitach group (C1) on engine (21). This group is used to monitor engine speed.

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).

3. 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.
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   Illustration 13	g01321378
   Monitor (A) Display (B) Keypad (C) Up key (D) Left key (E) Down key (F) Right key (G) Cancel key (H) Home key (I) OK key (J) Menu key

4. Start Service Mode and input a fixed power shift pressure of 2700 kPa (390 psi).

   1. Press menu key (J).

      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 (I).
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      Illustration 14	g01148206

   4. After OK key (I) is pressed, the screen in Illustration 14 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 (I) 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 (I).

   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 (I).

   10. 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).

   11. 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 sensor. Adjust the value on the monitor until the desired power shift pressure is attained on the pressure sensor that is connected to the pressure tap for power shift pressure. The actual power shift pressure must be 2700 kPa (390 psi) on the pressure sensor.

       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 15	g03413178
   Portable hydraulic tester (flow meter) (D1) Portable hydraulic tester (flow meter) (26) Valve

5. Turn valve (26) on portable hydraulic tester (D1) clockwise. Record pump flow at each of the following pressures in Table 1. Use a pressure sensor at pressure tap (16) to monitor the drive pump delivery pressure or use a pressure tap to monitor the delivery pressure of the idler pump.

   Note: To perform flow measurements for either one of the pumps, the other pump must not be under load.