311B and 312B Excavators Hydraulic System Caterpillar

Gear Pump (Pilot) - Test - 311B

Usage:

311B 2LS

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Illustration 1	g00383952
Flow meter tool layout (1) Swing motor (2) Connector at swing motor (3) Tee (4) Makeup line (5) Main control valves (6) Cap (7) 4C-9910 Portable hydraulic tester (flow meter) (8) Pilot line (9) Pilot oil manifold (10) Pressure tap at pilot oil manifold (11) 8T-0856 Pressure gauge (20) 6V-3989 Unvalved nipple (21) 6V-4143 Coupler assembly (29) 6V-3014 Hose (30) O-Ring seal (31) 5P-0201 Hose (32) 5P-1010 Sleeve (33) 4C-8767 Coupling (34) 7M-8484 O-Ring seal (35) 4C-6481 Coupler assembly (36) 4C-6482 Nipple assembly (37) 4I-6141 Coupling assembly (38) 8C-9026 Adapter (39) 6K-6307 O-Ring seal (42) 3J-7354 O-Ring seal (43) Union (45) Reducer (46) Nut

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Illustration 2	g00388734
Circuit diagram (1) Swing motor (2) Connector (3) Tee (4) Makeup line (5) Main control valves (6) Cap (7) Portable hydraulic tester (8) Pilot line (9) Pilot oil manifold (10) Pressure tap (11) Pressure gauge (12) Engine (13) Multitach (14) Pilot pump

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Illustration 3	g00388736
Top of main control valves (8) Pilot line

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Illustration 4	g00388739
Pilot oil manifold compartment (9) Pilot oil manifold (10) Pressure tap (15) Pilot relief valve

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Illustration 5	g00344084
Portable hydraulic tester (flow meter) (7) Portable hydraulic tester (flow meter) (13) Multitach (16) Valve (flow meter)

Preparation

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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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NOTICE

Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the product. Be prepared to collect the fluid with suitable containers before opening any compartment or disassembling any component containing fluids. Refer to Special Publication, NENG2500, "Caterpillar Tools and Shop Products Guide" for tools and supplies suitable to collect and contain fluids on Caterpillar products. Dispose of all fluids according to local regulations and mandates.

Position the machine on level ground.
Stop the engine.
Release the pressure in the hydraulic system. Refer to Testing And Adjusting, "Hydraulic System Pressure - Release".
Install the following tools in accordance with the circuit diagram. Refer to Illustration 1 and Illustration 2.
1. Install 6000 kPa (870 psi) pressure gauge (11) at pressure tap (10) on pilot oil manifold (9).
2. Install multitach (13) on engine (12).
3. Remove pilot line (8) from the connector on top of the main control valves (5). Install cap (6) on the connector at the main control valves (5).
4. Disconnect makeup line (4) from connector (2) of swing motor (1).
5. Install tee (3) at connector (2).
6. Connect makeup line (4) to tee (3).
7. Install portable hydraulic tester (7) between pilot line (8) and makeup line (4).
Start the engine.
Place the machine controls at the following settings: Power Mode, engine speed dial "10" and AEC switch OFF.
Reference: Make reference to Testing And Adjusting, "Operational Checks" for engine rpm settings.
Increase the hydraulic oil temperature to 55° ± 5°C (131° ± 9°F).

Test

Turn valve (16) on portable hydraulic tester (7) clockwise until pressure gauge (11) at pressure tap (10) shows a reading of 4100 ± 200 kPa (595 ± 30 psi).
Record the pilot pump flow at 4100 ± 200 kPa (595 ± 30 psi) in the following table.

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Table 1
Pump Flow Test
Oil temperature C° (F°)
Engine speed (rpm)
Flow measured liter/min (US gpm)
Flow corrected liter/min (US gpm)
Specification for pump flow liter/min (US gpm)	New	14 (3.7)⁽¹⁾
Specification for pump flow liter/min (US gpm)	Service limit	12 (3.2)

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⁽¹⁾	Minimum pump flow

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

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