349F and 352F Excavators Hydraulic System Pump Control (Negative Flow) - Test Caterpillar

Specification

Illustration 1	g03120777
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 only during 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.

Preliminary Test

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

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

• 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	g02535237
Tooling (C)

Illustration 4	g02146945
Tooling (D) (Flow meter tool layout)

ReferenceRefer 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

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

Illustration 5	g02405217
Pump compartment (1) Pressure tap (delivery pressure for drive pump) (2) Pressure tap (delivery pressure for idler pump) (3) Pressure tap (power shift pressure) (4) Delivery line for drive pump (5) Delivery line for idler pump (6) Negative flow control line (drive pump) (7) Negative flow control line (idler pump)

1. Position the machine on level ground.

2. Stop the engine.

3. Release 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 6	g02149462
Flow meter tool layout Tooling (D) (4) Delivery line for drive pump (5) Delivery line for idler pump (8) Bolt (9) Washer (10) Half flange (11) Seal (12) Makeup line (13) Seal (14) Elbow

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

   1. Disconnect delivery line (4) from the drive pump or delivery line (5) from the idler pump.

   2. Install seal (11) , half flanges (10) , and blocking cover (D18) to the end of the delivery line with bolts (8) and washers (9) .

   3. Assemble and install seal (D17) , adapter (D16) , seals (D4) , fitting (D12) , seal (D11) , plug (D10) , and fitting (D5) on the drive pump by using half flanges (D15) , bolts (D13) , and washers (D14) .
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   Illustration 7	g02149639
   Swing motor (top view) (12) Makeup line (13) Seal (14) Tee

   4. Disconnect makeup line (12) from tee (14) at the right swing motor.

   5. Assemble and install seals (D20) , tee (D21) , elbow (D19) , seal (D4) , and fitting (D5) to tee (14) at the swing motor.

   6. Connect seal (13) and makeup line (12) to tee (D21) .

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

7. Connect portable hydraulic tester (D) and test hoses between coupling assembly at the drive pump or the idler pump and coupling assembly at the swing motor.

8. Attach a 41,368 kPa (6,000 psi) pressure sensor to pressure tap (1) for delivery pressure of the drive pump. Attach a 41,368 kPa (6,000 psi) pressure sensor to pressure tap (2) for delivery pressure of the idler pump.

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Illustration 8	g02404719
Pump compartment (6) Negative flow control line (drive pump) (7) Negative flow control line (idler pump) (15) Pressure tap (negative flow for drive pump) (16) Pressure tap (negative flow for idler pump)

9. Attach a 3447 kPa (500 psi) pressure sensor to pressure tap (15) for negative flow control pressure for the drive pump. Attach a 3447 kPa (500 psi) pressure sensor to pressure tap (16) for negative flow control pressure for the idler pump.

10. Install tooling (C) on the engine 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

4. Enter the service mode.

   1. Input the password "9992".

   2. Select "Override Parameters".

5. Set the engine speed to 1800 rpm.

6. Override "Pump Flow Limit Pressure" to 2500 kPa (363 psi). Confirm the pump flow limit pressure measurement at pressure tap (15) or pressure tap (16) .

   Note: Override pump flow limit pressure back to 4000 kPa (580 psi) before attempting to enter a second override value.

7. Override power shift pressure to 2000 kPa (290 psi). Confirm the power shift pressure setting at pressure tap (3) .

   Note: Override power shift pressure back to 4000 kPa (580 psi) before attempting to enter a second override value.

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Illustration 9	g02599896
Portable hydraulic tester (flow meter) (D1) Portable hydraulic tester (flow meter) (17) Valve

8. Turn valve (17) on the portable hydraulic tester clockwise until pump pressure is at 6900 kPa (1000 psi). Use the pressure sensor at pressure tap (1) to monitor the delivery pressure of the drive pump or use pressure tap (2) to monitor the delivery pressure of the idler pump.

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