385B Excavator Hydraulic System Caterpillar

Illustration 1	g00556725
(F) Operator monitor panel

Note: Before starting main pump flow tests, check operator monitor panel (F) for normal operation. If no faults are present, perform the operational check. Refer to Testing And Adjusting, "Operational Checks".

Illustration 2	g00546818
Tooling setup (I) (1) 8T-4193 Bolt (2) 5P-8077 Half flange (3) Delivery line (front pump) (4) Delivery line (rear pump) (5) 1P-3705 Rectangular seal (6) 7I-7132 Cover (7) Front pump (8) Rear pump (9) 174-4356 Pump adapter (10) 2S-4078 O-ring seal (11) 174-4360 90 Degree Elbow (12) 3J-1907 O-Ring Seal (13) 9S-4191 Plug (14) 4C-5093 Nipple assembly (15) 4C-5094 Coupler assembly (16) 4C-6461 Coupling (17) 5P-0477 Sleeve (18) 5P-0202 Hose (19) 9U-6807 45 Degree Coupling (20) 6K-6307 O-ring seal (21) 4C-9910 Portable hydraulic tester (flow meter) (22) 9U-5229 Union (23) 4C-5086 45 Degree Coupling (24) Return port

Front 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. Install the following tools in accordance with Tooling setup (I). Refer to Illustration 2.

   Note: In order to prevent the loss of a large amount of hydraulic oil, a vacuum should be put on the hydraulic tank. Use a FT-2674 Vacuum Cap for this procedure.

   1. Disconnect delivery line (3) from front pump (7) .

   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 3	g00855117
   Main control valve (rear)

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

   4. Install coupling (23) and seal (10) in return port (24). Install nipple assembly (14) and seal (10) to coupling (23) .
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   Illustration 4	g00556696
   (21) Portable hydraulic tester (flow meter) (45) Multitach group (46) Valve

   5. Connect flow meter (21) between front pump (7) and nipple assembly (14) .

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

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Illustration 5	g00856623
Tooling setup (II) (view of main pump regulators) (A) Test hose (B) Test hose (C) Front pump regulator (D) Test hose (25) 8T-0861 Pressure gauge (26) 6V-3965 Nipple (27) 6V-4143 Coupler assembly (28) 6V-3014 Hose assembly (29) Pressure tap (power shift pressure) (30) 3E-2310 Tee (31) 6V-3965 Pressure tap (load signal pressure) (32) 6V-8730 Face Seal Union (33) 6V-8397 O-ring seal (34) Hose for load signal (front pump) (35) 8T-8902 Tee (36) 3J-1907 O-ring seal (37) 6V-3965 Nipple (38) Pressure tap (front pump delivery pressure) (39) 6V-9829 Cap assembly (43) Hose for load signal (rear pump)

5. Install the following tools in accordance with Tooling setup (II). Refer to Illustration 10.

   1. Disconnect hose for load signal (rear pump) (43) from the tee at front pump regulator (C) .

   2. Disconnect hose for load signal (front pump) (34) from the tee at front pump regulator (C) .

   3. Connect hose for load signal (34) to hose for load signal (43) with 6V-8730 Face Seal Union .

   4. Remove the tee from front pump regulator (C). Install 3E-2310 Tee in front pump regulator (C) .

   5. Connect test hose (A) to pressure tap (29). This is used to monitor power shift pressure.

   6. Connect test hose (B) to pressure tap (31). This is used to monitor front pump delivery pressure.

   7. Install seal (33) and tee (35) to tee (30) .

   8. Install seal (33) and cap (39) on tee (35) .

   9. Install seal (36) and nipple (37) in tee (35) .

   10. Connect test hose (D) between nipple (37) and front pump pressure tap (38) .

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Illustration 6	g00556697
(47) Electronic Technician ( ET)

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Illustration 7	g00871558
Location of service connector (48) Service connector

6. Connect Electronic Technician (E.T.) (47) to service connector (48). This is used to enter a fixed power shift pressure.

Rear 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. Install the following tools in accordance with Tooling setup (I). Refer to Illustration 2.

   Note: In order to prevent the loss of a large amount of hydraulic oil, a vacuum should be put on the hydraulic tank. Use a FT-2674 Vacuum Cap for this procedure.

   1. Disconnect delivery line (4) from front pump (8) .

   2. Install seal (5), half flanges (2) and cover (6) to the end of delivery line (4) by using bolts (1) .
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   Illustration 8	g00855117
   Main control valve (rear)

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

   4. Install coupling (23) and seal (10) in return port (24). Install nipple assembly (14) and seal (10) to coupling (23) .
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   Illustration 9	g00556696
   (21) Portable hydraulic tester (flow meter) (45) Multitach group (46) Valve

   5. Connect flow meter (21) between rear pump (8) and nipple assembly (14) .

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

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Illustration 10	g00856422
Tooling setup (III) (view of main pump regulators) (A) Test hose (B) Test hose (D) Test hose (E) Rear pump regulator (25) 8T-0861 Pressure gauge (26) 6V-3965 Nipple (27) 6V-4143 Coupler assembly (28) 6V-3014 Hose assembly (29) Pressure tap (power shift pressure) (33) 6V-8397 O-ring seal (35) 8T-8902 Tee (36) 3J-1907 O-ring seal (37) 6V-3965 Nipple (39) 6V-9829 Cap assembly (40) Pressure tap (load signal pressure) (41) Elbow (42) 6V-9508 Face seal plug (43) Hose for load signal (rear pump) (44) Pressure tap (rear pump delivery pressure)

5. Install the following tools in accordance with Tooling setup (III). Refer to Illustration 10.

   1. Disconnect hose for load signal (rear pump) (43) from elbow (41) at rear pump regulator (E) .

   2. Install plug (42) and seal (33) to the end of hose for load signal (43) .

   3. Connect test hose (A) to pressure tap (29). This is used to monitor power shift pressure.

   4. Connect test hose (B) to pressure tap (40). This is used to monitor rear pump delivery pressure.

   5. Install seal (33) and tee (35) to elbow (41) .

   6. Install seal (33) and cap (39) on tee (35) .

   7. Install seal (36) and nipple (37) in tee (35) .

   8. Connect test hose (D) between nipple (37) and pressure tap (44) .

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Illustration 11	g00556697
(47) Electronic Technician ( ET)

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Illustration 12	g00871558
Location of service connector (48) Service connector

6. Connect Electronic Technician (E.T.) (47) to service connector (48). This is used to enter a fixed power shift pressure.

Test

Note: The front pump and the rear pump must be tested separately. The following procedure is used for testing both pumps.

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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.

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Illustration 13	g00726210
(C) Display for Digging Mode (D) Key for Digging Mode

2. 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.

3. Set a fixed fan speed of 873 rpm. Refer to Testing and Adjusting, "Fan Motor Speed (Hydraulic and Radiator Cooling) - Test and Adjust".

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

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

6. Use Electronic Technician ( ET) in order to set a fixed power shift pressure of 2285 ± 50 kPa (330 ± 7.5 psi).

   Note: Always monitor the actual power shift pressure on the pressure gauge at test hose (A). The actual power shift pressure must be 2285 ± 50 kPa (330 ± 7.5 psi) on the pressure gauge.

   Note: The pump flow changes approximately 33 L/min (8.7 US gpm) for each 100 kPa (14 psi) of power shift pressure.

7. Turn valve (46) on flow meter (21) clockwise. Record pump flow at each of the following pressures in Table 1. Use the pressure gauge on test hose (B) to monitor pump delivery pressure.

Illustration 14	g00856450
P-Q characteristic curve

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

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.