385B Excavator Hydraulic System Caterpillar

Illustration 1	g00558096
Flow meter tool layout (S) Swing pump (1) 8T-4193 Bolt (2) 5P-8077 Half flange (3) Delivery line (front pump) (5) 1P-3705 Rectangular seal (6) 7I-7132 Cover (9) 1P-3705 Rectangular seal (10) 174-4356 Adapter (11) 2S-4078 O-ring seal (12) 5P-8077 Half flange (13) 174-4360 Elbow (14) 3J-1907 (15) 9S-4191 O-Ring Plug (16) 4C-5093 Nipple assembly (17) 4C-5094 Coupler assembly (18) 4C-6461 Coupling (19) 5P-0477 Sleeve (20) 5P-0202 Hose (21) 4C-9910 Portable hydraulic tester (flow meter) (22) 6K-6307 O-ring seal (23) 9U-5229 Union (24) Return port (25) 4C-5086 45 Degree Coupling

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. Install the following tools in accordance with the flow meter tool layout. Refer to Illustration 1.

   1. Disconnect delivery line (3) from swing pump (S) .

   2. Install seal (5), half flanges (2) and cover (6) to the end of delivery line (3) by using bolts (1) .
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   Illustration 2	g00855117
   Main control valve (rear)

   3. Remove plug (24) from the return port.

   4. Install coupling (25) and seal (11) in return port (24). Install nipple assembly (16) and seal (11) to coupling (25) .
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   Illustration 3	g00556696
   (21) Portable hydraulic tester (flow meter) (45) Multitach group (46) Valve

   5. Connect flow meter (21) and the test hoses between nipple assembly (16) at swing pump (S) and nipple assembly (16) at return port (24) .

   6. Install multitach (45) on the engine. This is used to monitor engine speed.

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Illustration 4	g00556697
(47) Electronic Technician ( ET)

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Illustration 5	g00871558
Location of service connector (48) Service connector.

5. Connect the Electronic Technician (ET) (47) to service connector (48). This is used to input a fixed amperage to the swashplate solenoid of the swing pump.

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Illustration 6	g00856328
Electrical connector

6. Install an ammeter at the electrical connector at the swashplate solenoid in order to measure the amperage that is sent from the machine electronic control module to the swashplate solenoid of the swing pump.

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Illustration 7	g00856310
Pilot manifold (49) Pressure tap

7. Connect a 6000 kPa (870 psi) pressure gauge to pressure tap (49) at the pilot manifold.

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Illustration 8	g00856335
Swing pump (26) Pressure tap

8. Connect a 60000 kPa (8700 psi) pressure gauge to pressure tap (26) at the swing pump. This is used to monitor the delivery pressure of the swing pump.

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Illustration 9	g00856314
Rear swing motor (51) Electrical connector

9. Disconnect electrical connector (51) from the swing brake solenoid in order to disable the swing circuit.

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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.

10. Start the engine.

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Illustration 10	g00726210
(C) Display for Digging Mode (D) Key for Digging Mode

11. Place the machine controls at the following settings: Engine speed dial "10", AEC switch OFF, Digging Mode and Gain/Response(normal). Refer to Testing and Adjusting, "Engine Performance - Test" for engine rpm settings.

12. Place the hydraulic activation lever in the UNLOCKED position.

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

14. Check the pilot oil pressure at the pressure gauge that is connected to pressure tap (49) of the pilot manifold. The pressure reading should indicate 4100 ± 100 kPa (595 ± 14 psi). If the pilot oil pressure is not within the specification, adjust the pilot relief valve. Refer to Testing and Adjusting, "Relief Valve (Pilot) - Test and Adjust" for information concerning the adjustment of the pilot relief valve.

15. Slowly move the swing joystick and ensure that the swing parking brake is activated.

16. Enter a value of "0.5 A" in ET for the swashplate solenoid at the swing pump. Check the ammeter. If the value at the ammeter is not 473 mA, increase or decrease the "0.5 A" value until the ammeter reads 473 mA.

    Note: Step 16 provides a fixed amperage of 473 mA to the swashplate solenoid in order to measure the output flow of the swing pump while the swing pump swashplate is maintained at a constant position.

17. Slowly, turn valve (46) on flow meter (21) clockwise until the delivery pressure is 7000 kPa (1025 psi). Use the pressure gauge at pressure tap (26) to monitor the delivery pressure of the swing pump.

18. Measure the flow rate.

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