Bench Test Procedure for Hydraulic Piston Pumps{5070} Caterpillar

Excavator:

313B (S/N: 9PR1-UP; BAS1-UP; AEX1-UP)

Introduction

© 2012 Caterpillar All Rights Reserved. This guideline is for the use of Caterpillar Dealers only. Unauthorized use of this document or the proprietary processes therein without permission may be violation of intellectual property law.

This Special Instruction includes test procedures for piston pumps. This Special Instruction also provides specifications. The technician should have a good understanding of hydraulic piston pumps. The technician should be educated in the operation of the hydraulic test bench. The test benches in this document are available through the Caterpillar Service Tool Division. Gather all necessary tooling before you need to hook up the pump. Some of the required tooling appears in a table at the end of this document. There are many possible variations of tooling that could be used. Not every possible variation can be listed.

For questions or additional information concerning this guideline, submit a feedback form in the Service Information System website. In order to address an urgent need, use the following to relay your request to Caterpillar Repair Process Engineering:

• Cat Dealer Technical Communicator

• Dealer Solution Network

• Cat Technical Representative

• Knowledge Network (online)

Canceled Part Numbers and Replaced Part Numbers

This document may not include all Canceled part numbers and replaced part numbers. Use NPR on SIS for information about Canceled part numbers and replaced part numbers. NPR will provide the current part numbers for replaced parts.

Safety

Show/hide table

Personal injury or death can result from improperly checking for a leak. Always use a board or cardboard when checking for a leak. Escaping air or fluid under pressure, even a pin-hole size leak, can penetrate body tissue causing serious injury, and possible death. If fluid is injected into your skin, it must be treated immediately by a doctor familiar with this type of injury.

Show/hide table

Hot oil and hot components can cause personal injury. Do not allow hot oil or hot components to contact skin.

Show/hide table

Pump test pressures in this guideline may exceed the normal operating range of the hydraulic test hoses utilized when connecting the tested pump to the test bench. However, the order of magnitude of these pressures is significantly below the burst strength of the Caterpillar "XT6" product. High pressure oil can escape through improperly assembled hoses and fittings. High pressure oil can also escape through poorly maintained hoses and fittings. High pressure oil may also leak through hose that has become damaged over the life of the hose due to the pressure levels that occur during test bench operation. Personal injury or death can result from improper hose & fitting inspection or improper hose replacement procedures. Escaping fluid under pressure can penetrate body tissue causing serious injury, and possible death. Thoroughly inspect all testing hoses, fittings, and quick disconnects prior to any testing operation. Check the assembly date tag or hose assembly log date for a hose life indicator. Replace all Test Bench hoses at a minimum of every 2 years or earlier if the hose or fittings appear to be damaged.

Summary

This procedure is specific to the type of pump and the type of control. Refer to the test specifications and the tooling at the end of this document.

Note: A paper copy of this document may not be the latest version. Go to the Service Information System (SIS) in order to view the latest version.

References

Connections for the Caterpillar Hydraulic Test Center

Illustration 1	g01063311
Connections for the Test Center (1) Flow control for discharge (2) "F3" flow meter inlet (3) "F4" flow meter inlet (4) Oil supply from the auxiliary pump (5) "F3" inlet for the flow meter with flow limiter (6) "F3"outlet for the flow meter with pressure control (7) Load sensing pressure (8) Signal pressure (9) "F4" outlet for the flow meter (10) Return to tank (11) Connections for case drain (12) Oil supply

Illustration 2	g01063312
Control and Gauges for the Test Center (13) Meter for speed and torque (14) Gauge for signal pressure (15) Control for signal pressure (16) Pressure gauge for auxiliary pump (17) Auxiliary pump flow (18) "F3" discharge pressure gauge (19) "F3" discharge flow (20) "F4" discharge pressure gauge (21) "F4" discharge flow (22) Auxiliary pump flow control (23) "F3" margin pressure (24) "F3" Load control for discharge pressure (25) "F4" Load control for discharge pressure

Connections for the Caterpillar Hydraulic Test Bench

Illustration 3	g01063314
Connections for the Test Bench (26) "Flow meter 1" loop and "Flow meter 2" loop (27) Oil Supply

Illustration 4	g01093468
Connections for the Test Bench (28) "Flow meter 2" loop (29) "Flow meter 1" loop (30) "Flow meter 2" outlet (31) Signal pressure line (32) "Flow meter 2" inlet (33a) "Flow meter 1" outlet (33b) Auxiliary oil supply outlet (34) Auxiliary oil supply inlet (35) "Flow meter 1" inlet

Illustration 5	g01063316
Control and Gauges for the Test Bench (36) Auxiliary oil supply pressure (37) Signal pressure (38) Control for signal pressure (39) "Flow meter 1" discharge pressure (40) Control for auxiliary oil supply pressure (41) "Flow meter 2" discharge pressure (42) Auxiliary oil supply control (43) "Flow meter 2" discharge flow (44) Discharge flow for auxiliary pump (45) "Flow meter 1" discharge flow (46) "Flow meter 1" load control (47) Speed and direction control (48) "Flow meter 2" load control

Port Locations

Illustration 6	g01439393
Typical port locations and adjustments (49) Pressure port for torque mode (50) Pressure port for negative flow control (51) Pressure port for negative flow control (opposite side) (52) Adjustment screw for variable orifice (equipped with the blade pump) (53) Fine control pressure port (54) Pump suction port (55) Gauge port for discharge pressure (one on each side) (56) Pump discharge port (both sides) (57) Adjustment screw for maximum angle (58) Pilot port (blade pump) (59) Case drain port (60) Discharge port for the blade pump (opposite side) (61) Suction port for the blade pump (62) Discharge port for the pilot pump

Pump Setup

1. Vent the following ports. Refer to Illustration 6.
   • Pressure port for negative flow control (50) and (51)

   • Pilot port (58)

   • Fine control pressure port (53)

   • Pressure port for torque mode (49)

2. Connect both pump discharge ports (56) to flow meter inlets on the test bench.

   Connect an 8T-0860 gauge to each gauge port for discharge pressure (55) and (56) .

3. Connect the discharge port for the pilot pump (62) to an in-line flow meter in order to measure the discharge for the pilot pump.

   Connect the discharge port for the blade pump (60) (if equipped) to a 4C-9910 Portable Hydraulic Tester . Connect the outlet of the 4C-9910 Portable Hydraulic Tester to tank.

4. Connect a 3 inch "NPT" tee to the suction flange. Connect the pump suction port (54) to the test bench oil supply. Connect remaining opening of the tee to the suction port for the blade pump (61) .

5. Carefully loosen the drain plug. This will release the case's air pressure in order to allow the case to fill with oil from the suction line.

6. Verify that the pump case is full of oil before rotating. Secure the drain plug (59).

7. Do not rotate the pump in the wrong direction. The correct direction of rotation will be stated on the pump. The direction of rotation is viewed from the input shaft end. Visually check the pump for proper rotation.

Test Procedure

Note: The hydraulic oil in the test bench should meet a contamination ISO rating of 16/13 or cleaner. The oil in the test bench should be one of the following.

• SAE 10W at 50 °C (122 °F) or

• Mobil DTE-11 at 46 °C (115 °F)

Illustration 7	g01015389
Typical power curve

Illustration 8	g01109823
Typical curve of negative flow control

1. Rotate the pump according to Step 1 of the test specifications. Listen for abnormal noise. Verify flow from the discharge port for the pilot pump (14). Verify flow from the discharge port for the blade pump (60). Verify that all connections are tight. Check for leaks around shaft seals. Check for leaks around the control valve.

   Run the pump for at least 5 minutes in order to raise the temperature of the oil and purge the system of air.

2. Use the following steps to verify the maximum displacement. Also, use the following steps to verify the control for constant horsepower. Both pumps will be tested at the same time. Compare actual flow rates to the given flow rates. The flow rates are supplied in the test specifications. Refer to Illustration 7 for an example of a power curve.

   1. Increase the input RPM. Increase the load to the discharge port for the blade pump (60) (if equipped) according to Step 2.a of the test specifications.

      If the flow rate for discharge is not within specifications, adjust the adjustment screw for maximum angle (57) .

      To decrease flow, loosen the locknut. Turn the adjustment screw for maximum angle (57) clockwise. To increase flow, loosen the locknut. Turn the adjustment screw for maximum angle (57) counterclockwise.

   2. Load both pumps to the value in Step 2.b of the test specifications.

      The pump is at the destroke point. The pump should now be under constant horsepower control. Equally cycle the load to both pumps. Cycle the load near the value in Step 2.b of the test specifications. This verifies the point of destroke. As the pump discharge pressure increases, the flow rate of the discharge should begin to drop.

   3. Load the pumps to the value in Step 2.c of the test specifications.

   4. Load the pumps to the value in Step 2.d of the test specifications.

      Note: The pump control may need to be disassembled if the flow rates for discharge are not within specifications. Refer to the flow specifications in Steps 2.b through 2.d.

Note: Step 3 applies only to machines that are equipped with a blade pump with a variable orifice. The variable orifice is used to regulate the available pump horsepower when the blade circuit is active. If the pump is not equipped with the variable orifice, go to Step 4.

3. Use the following steps to verify the adjustment screw for variable orifice (52). Both pumps will be tested at the same time. Compare the actual flow rates to the values in the test specifications. Refer to Illustration 7 for an example of a power curve.

   Decrease all pressures to zero. Decrease the pump input to zero RPM. Connect a hose from the discharge port (blade pump) (60) to the pilot port (blade pump) (58) .

   1. Increase the input RPM according to Step 3.a of the test specifications. Increase the load to the discharge port for the blade pump (60) (if equipped) according to Step 3.a of the test specifications.

   2. Load both pumps to the value in Step 3.b of the test specifications.

      The pump should be at the destroke point. The pump should now be under constant horsepower control. Slowly cycle the load to both pumps. Start with a load that is lower than the value in Step 3.b. Increase the load. Verify that the pump is at the point of destroke at the value in Step 3.b of the test specifications.

      If the flow rates do not match the test specifications, the variable orifice must be adjusted.

      To increase flow, loosen the locknut. Turn the adjustment screw for variable orifice (52) counterclockwise. To decrease flow, turn the adjustment screw for variable orifice (52) clockwise.

   3. Load both pumps to the value in Step 3.c of the test specifications.

   4. Load both pumps to the value in Step 3.d of the test specifications.

4. The following steps verify the operation of the negative flow control. Both pumps will be tested at the same time. Compare the actual flow rates at each step to the values in the test specifications. Refer to Illustration 8 for an example of a curve for negative flow control.

   Decrease the input RPM and all pressures to zero. Disconnect the hose from the discharge port for the blade pump (60). Disconnect the hose from the pilot port (blade pump) (58). Leave the pilot port (blade pump) (58) open to the atmosphere. Connect the oil supply for signal pressure to 196-8722 Tee . Connect both pressure ports for negative flow control (50) and (51) to the tee.

   1. Increase the input RPM and discharge pressure to both pump discharge ports (56). Increase signal pressure from the test bench to the pressure ports for negative flow control (50) and (51) according to Step 4.a of the test specifications.

      The pump should be at the destroke point. The pump should now be under negative flow control. Slowly cycle the negative flow control pressure. Start with a pressure that is lower than the value in Step 4.a. Increase the pressure. Verify that the pump is at the point of destroke at the value in Step 4.a of the test specifications. As the pressure of the negative flow control increases past the value in Step 4.a, the discharge flow should begin to decrease. If either pump's point of destroke is not correct, adjust the negative flow control for that pump. To adjust the negative flow control, shims must be added or removed.

   2. Increase control pressure to the pressure ports for negative flow control (50) and (51) according to Step 4.b of the test specifications.

   3. Increase control pressure to the pressure ports for negative flow control (50) and (51) according to Step 4.c of the test specifications.

Show/hide table

Hot oil and hot components can cause personal injury. Do not allow hot oil or hot components to contact skin.

Reduce all discharge pressures to zero. Reduce the RPM to zero. Remove the component from the bench. Drain the oil from the pump. Cap all ports. Plug all ports.

Test Specifications

Tooling