994K Wheel Loader Machine Systems Caterpillar

Pump Performance (Brake) - Test

Usage:

994K MM9

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To prevent personal injury when checks are made while the machine is in operation, make sure only approved personnel are on the machine. Keep other personnel off the machine and in view of the operator. Make sure checks are done in an open area.

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Personal injury or death can result from sudden machine movement.
Sudden movement of the machine can cause injury to persons on or near the machine.

To prevent injury or death, make sure that the area around the machine is clear of personnel and obstructions before operating the machine.

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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, "Dealer Service Tool Catalog" for tools and supplies suitable to collect and contain fluids on Cat products. Dispose of all fluids according to local regulations and mandates.

Specification

Reference: For more information on the specifications for the brake hydraulic pumps, refer to Specifications for your machine.

For any pump test, the pump flow at 690 kPa (100 psi) will be larger than the pump flow at 6900 kPa (1000 psi) if the pump is operating at the same rpm. The pump flow is measured in L/min (US gpm).

The difference between the pump flow of two operating pressures is the flow loss.

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Table 1
Method to determine the flow loss
	Pump flow at 690 kPa (100 psi)
−	Pump flow at 6900 kPa (1000 psi)
	Flow loss

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Table 2
Example of determining the flow loss
	217.6 L/min (57.5 US gpm)
−	196.8 L/min (52.0 US gpm)
	20.8 L/min (5.5 US gpm)

Flow loss that is expressed as a percentage of pump flow is used as a measure of pump performance.

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Table 3
Method of determining percent of flow loss
Flow loss (L/min or US gpm)	×	100	=	Percent of flow loss
Pump flow at 690 kPa (100 psi)

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Table 4
Example of determining percent of flow loss
20.8 L (5.5 US gal)	×	100	=	9.5%
217.6 L/min (57.5 US gpm)

Note: The values in the examples are not set values for any specific pump or for any specific pump condition. See the Specification for your machine for the pump flow of a new pump at 690 kPa (100 psi) and at 6900 kPa (1000 psi).

Introduction

This test is designed to determine whether a pump is operating within design parameters.

For any pump test, the pump flow at 690 kPa (100 psi) will be larger than the pump flow at 6900 kPa (1000 psi) if the pump is operating at the same rpm. The pump flow is measured in L/min (US gpm).

The difference between the pump flow of two operating pressures is the flow loss.

Required Tools

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Illustration 1	g02571852
Tooling (A) 198-4240 Digital Pressure Indicator Gp

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Table 5
Required Tools
Tool	Item	Qty	Part No	Description
A			198-4240	Digital Pressure Indicator Gp
	A1	1	198-4234	Digital Indicator
	A2	1	198-4237	Pressure Sensor Gp (0 to 3,445 kPa (0 to 500 psi))
	A2	1	198-4238⁽¹⁾	Pressure Sensor Gp (0 to 34,450 kPa (0 to 5,000 psi))
	A2	1	198-4239	Pressure Sensor Gp (0 to 41,368 kPa (0 to 6,000 psi))
	A2	1	251-9600⁽²⁾	Pressure Sensor Gp (0 to 68,900 kPa (0 to 10,000 psi))
	A3	1	198-4236	Adapter Cable As

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⁽¹⁾	This sensor must be purchased separately, it is not included in the 198-4240 Digital Pressure Indicator Gp
⁽²⁾	This sensor can only be used on large diameter pressure taps like 6V-3965 Fitting.

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Illustration 2	g02726620

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Table 6
Required Tools
Tool	Item	Qty	Part No	Description
B	B1	1	8T-0855	Pressure Gauge (0 TO 4,000 kPa (0 TO 580 psi))
	B1	1	8T-0857	Pressure Gauge (0 TO 10,000 kPa (0 TO 1,450 psi))
	B1	1	8T-0858	Pressure Gauge (0 TO 16,000 kPa (0 TO 2,300 psi))
	B1	1	8T-0859	Pressure Gauge (0 TO 25,000 kPa (0 TO 3,600 psi))
	B2	1	6V-3989	Fitting
	B3	2	6V-4143	Quick Connect Coupler
	B4	1	177-7860	Hose As 3.0 m (10 ft)
	B4	1	177-7861	Hose As 4.3 m (14 ft)
	B4	1	177-7862	Hose As 5.5 m (18 ft)

Select from tooling (A) or tooling (B) for the suitable gage for the pressure being tested.

Use a suitable flow meter for the pump flow being tested.

Test Preparation

Before proceeding to the test procedure that follows, complete the procedures:

Reference: For additional information about preparing the machine for troubleshooting the machine, refer to the Service Manual module Troubleshooting, "Machine Preparation for Troubleshooting" for the machine that is being serviced.

Test Procedure

Test on the Machine

Install a flow meter. Run the engine at high idle. Measure the pump flow at 690 kPa (100 psi) and at 6900 kPa (1000 psi). Use these values in Formula 1 in Table 7.

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Table 7
	Formula 1
	Pump flow at 690 kPa (100 psi)
−	Pump flow at 6900 kPa (1000 psi)	×	100	=	Percent of flow loss
	Pump flow at 690 kPa (100 psi)	×	100	=	Percent of flow loss

Test on the Bench

If the bench test can be performed at 6900 kPa (1000 psi) and at full pump rpm, determine the percent of flow loss by using Formula 1 in Table 7.

If the bench test cannot be performed at 6900 kPa (1000 psi) or at full pump rpm, run the pump shaft at 1000 rpm.

Measure the pump flow at 690 kPa (100 psi) and at 6900 kPa (1000 psi). Use these values in the top portion of Formula 2 in Table 8.

For the bottom part of the formula, run the pump shaft at 2000 rpm. Measure the pump flow at 690 kPa (100 psi).

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Table 8
	Formula 2
	Pump flow at 690 kPa (100 psi)
−	Pump flow at 6900 kPa (1000 psi)	×	100	=	Percent of flow loss
	Pump flow at 690 kPa (100 psi) and at 2000 rpm	×	100	=	Percent of flow loss