- Excavator:
- 311C (S/N: CKE1-UP; CLK1-UP)
Pump Control (Negative Flow) - Test
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.
| Flow Test Chart | |||
| Item Number | Part Number | Part Description | Quantity |
| 5 | 4C-6482 | Fitting | 2 |
| 6 | 7M-8485 | O-Ring Seal | 2 |
| 7 | 4C-5089 | Elbow | 1 |
| 9 | 6V-9746 | O-Ring Seal | 6 |
| 10 | 6V-9511 | Face Seal Plug | 1 |
| 12 | 4I-6140 | Coupling | 1 |
| 14 | 6V-9853 | Swivel Elbow | 1 |
| 15 | 6V-9839 | Swivel Tee | 1 |
| 26 | 6V-8397 | O-Ring Seal | 2 |
| 27 | 3J-1907 | O-Ring Seal | 2 |
| 28 | 6V-3965 | Fitting As | 2 |
| 29 | 6V-4143 | Coupler | 2 |
| 30 | 177-7860 | Hose As | 1 |
| 33 | 6V-3989 | Fitting | 1 |
| 34 | 8T-0855 | Pressure Gauge | 1 |
| 35 | 5I-4376 | Fitting | 1 |
| 36 | 6V-9508 | Face Seal Plug | 1 |
| 37 | 177-7860 | Hose As | 1 |
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| Illustration 1 | g00792493 |
Flow meter tool layout (8) Delivery line (right pump) (11) Delivery line (left pump) (13) Makeup line (swing motor) (16) Swing motor (17) Right pump (18) Left pump (22) Elbow (23) Valve (24) Setup of basic flow meter and hoses | |
Right Pump
| 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. |
Note: Perform the test for the right pump and the test for the left pump one at a time.
 | |
| Illustration 2 | g00788758 |
Pump compartment (8) Delivery line (right pump) (11) Delivery line (left pump) (17) Right pump (18) Left pump (19) Pressure tap (right pump delivery pressure) (20) Pressure tap (left pump delivery pressure) (21) Pressure tap (power shift pressure) (25) Negative flow control line (right pump) (38) Negative flow control line (left pump) | |
- 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.
- Assemble the basic flow meter and hoses.
Note: Refer to Testing and Adjusting, "Flow Meter and Hose Setup (Basic)" for the procedure to assemble these parts.
- Disconnect delivery line (8) from right pump (17) .
- Install seal (9) and plug (10) to the end of delivery line (8) .
- Assemble and install fitting (5), seal (6), elbow (7), and seal (9) on right pump (17) .
- Disconnect makeup line (13) from elbow (22) at swing motor (16) .
Show/hide table
Illustration 3 g00788759
(13) Makeup line (swing motor)
(16) Swing motor
(22) Elbow
- Assemble and install fitting (5), seal (6), coupling (12), seal (9), elbow (14), seal (9), swivel tee (15), and seal (9) to elbow (22) .
- Install seal (9) and makeup line (13) to swivel tee (15) .
- Connect the flow meter between fitting (5) at right pump (17) and fitting (5) at the swing motor.
- Connect a 60000 kPa (8700 psi) pressure gauge to pressure tap (19) for right pump delivery pressure.
- Install a multitach group on the engine. This is used to monitor engine speed.
- Disconnect negative flow control line (25) from right pump (17). Install seal (26) and plug (36) to the end of negative flow control line (25) .
Show/hide table
Illustration 4 g00788887
(25) Negative flow control line (right pump)
Show/hide table
Illustration 5 g00824412
Tool Setup
(17) Right pump
(18) Left pump
(21) Pressure tap (power shift pressure)
(25) Negative flow control line (right pump)
(26) O-Ring seal
(27) O-Ring seal
(28) Fitting assembly
(29) Coupler
(30) Hose
(33) Fitting
(34) Pressure gauge
(35) Fitting
(36) Face seal plug
(37) Hose
(38) Negative flow control line (left pump)
- Connect fitting (35) to the elbow at the negative flow signal pressure port of right pump (17) .
- Connect one end of test hose (30) to fitting (35) .
- Connect the other end of test hose (30) to power shift pressure port (21) for the power shift pressure.
- Connect one end of test hose (37) to fitting (35) .
- Connect 6000 kPa (870 psi) pressure gauge (34) to the other end of test hose (37) .
- Assemble the basic flow meter and hoses.
Left Pump
| 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. |
Note: Perform the test for the right pump and the test for the left pump one at a time.
| | |
| Illustration 6 | g00788758 |
Pump compartment (8) Delivery line (right pump) (11) Delivery line (left pump) (17) Right pump (18) Left pump (19) Pressure tap (right pump delivery pressure) (20) Pressure tap (left pump delivery pressure) (21) Pressure tap (power shift pressure) (25) Negative flow control line (right pump) (38) Negative flow control line (left pump) | |
- 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.
- Assemble the basic flow meter and hoses.
Note: Refer to Testing and Adjusting, "Flow Meter and Hose Setup (Basic)" for the procedure to assemble these parts.
- Disconnect delivery line (11) from left pump (18) .
- Install seal (9) and plug (10) to the end of delivery line (11) .
- Assemble and install fitting (5), seal (6), elbow (7), and seal (9) on left pump (18) .
- Disconnect makeup line (13) from elbow (22) at swing motor (16) .
Show/hide table Illustration 7 g00788759
(13) Makeup line (swing motor)
(16) Swing motor
(22) Elbow
- Assemble and install fitting (5), seal (6), coupling (12), seal (9), elbow (14), seal (9), swivel tee (15), and seal (9) to elbow (22) .
- Install seal (9) and makeup line (13) to swivel tee (15) .
- Connect the flow meter between fitting (5) at left pump (18) and fitting (5) at the swing motor.
- Connect a 60000 kPa (8700 psi) pressure gauge to pressure tap (20) for left pump delivery pressure.
- Install a multitach group on the engine. This is used to monitor engine speed.
- Disconnect negative flow control line (38) from left pump (18). Install seal (26) and plug (36) to the end of negative flow control line (38) .
Show/hide table
Illustration 8 g00788889
(38) Negative flow control line (left pump)
Show/hide table Illustration 9 g00824412
Tool Setup
(17) Right pump
(18) Left pump
(21) Pressure tap (power shift pressure)
(25) Negative flow control line (right pump)
(26) O-Ring seal
(27) O-Ring seal
(28) Fitting assembly
(29) Coupler
(30) Hose
(33) Fitting
(34) Pressure gauge
(35) Fitting
(36) Face seal plug
(37) Hose
(38) Negative flow control line (left pump)
- Connect fitting (35) to the elbow at the negative flow signal pressure port of left pump (17) .
- Connect one end of test hose (30) to fitting (35) .
- Connect the other end of test hose (30) to power shift pressure port (21) for the power shift pressure.
- Connect one end of test hose (37) to fitting (35) .
- Connect 6000 kPa (870 psi) pressure gauge (34) to the other end of test hose (37) .
- Assemble the basic flow meter and hoses.
Test
Note: Perform the test for the right pump and the test for the left pump one at a time.
 |
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. |
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- Start the engine.
- Place the engine speed dial in the HIGH IDLE position. Maintain the maximum no-load speed at 1980 ± 50 rpm with the manual low idle switch OFF.
- Increase the hydraulic oil temperature to 55° ± 5°C (131° ± 9°F).
- Adjust the high pressure setting of the power shift pressure until the pressure reading at pressure gauge (34) is 2350 kPa (340 psi).
Reference: Refer to Testing and Adjusting, Electrical and Electronic System, "Proportional Reducing Valve - Calibrate".
Note: The Caterpillar Electronic Technician (ET) can also be used for the adjustment of pressure settings.
- Turn valve (23) on the flow meter clockwise until the pump delivery pressure is 6850 kPa (1000 psi).
- Record the negative flow rate in Table 2.
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| Illustration 10 | g00788874 |
Pressure/Flow characteristic curve | |
| Negative Flow Control at 2350 kPa (340 psi) |
||
|---|---|---|
| Oil Temperature °C (°F) | Right pump | |
| Left pump | ||
| Engine speed (rpm) | Right pump | |
| Left pump | ||
| Flow measured liter/min (US gpm) | Right pump | |
| Left pump | ||
| Flow corrected liter/min (US gpm) | Right pump | |
| Left pump | ||
| Specification for negative flow rate liter/min (US gpm) | New | 63 ± 6 (16.6 ± 1.6) |
| Service limit | 51 (13.5) |
|
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.
| Corrected flow | = | Measured flow x 1800 rpm |
| Measured rpm |
Flow measurements must be done in pressure rise.
Return the high pressure setting of the power shift pressure to 2500 kPa (360 psi).