422E, 428E, 432E, 434E, 442E and 444E Backhoe Loaders Hydraulic and Steering System Caterpillar

Pump Flow - Test

Usage:

428E DPH

Pump Flow Test for the 422E and 428E Backhoe Loaders

Show/hide table

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

Note: Pump failure will generally begin with loss of efficiency at low idle, and in conditions that have high oil operating temperature. If the pump efficiency improves after increasing the speed of the engine, or after the oil is allowed to cool, test the pump first.

For the pump test at a given rpm, the pump flow at the discharge pressure 3500 kPa (507 psi) will be larger than the pump flow at 10000 kPa (1450 psi). The difference between the pump flow of the two operating pressures is the flow loss.

Show/hide table

Table 1
Method for determining flow loss
	Pump flow at 3500 kPa (507 psi)
−	Pump flow at 10000 kPa (1450 psi)
	Flow loss

Show/hide table

Table 2
Example of determining flow loss
	99 L (26 US gal)
−	95 L/min (25 US gpm)
	4 L/min (1 US gpm)

The flow loss is used to measure the pump performance. Flow loss is expressed as a percent of pump flow.

Show/hide table

Table 3
Method of determining percent of flow loss
Flow loss (L/min or US gpm)	×	100	Percent of flow loss
Pump flow at 3500 kPa (507 psi)

Show/hide table

Table 4
Example of determining percent of flow loss
4 L/min (1 US gpm)	×	100	=	4%
99 L (26 US gal)

Machine Test

Install the flow meter with a needle valve between the Stick A and B work ports. The lever needs to be at full actuation while you run this test. Run the engine at high idle. Measure the pump flow at 3500 kPa (507 psi) and at 10000 kPa (1450 psi). Use these values to determine the flow loss.

Show/hide table

Table 5
Method for determining flow loss
	Pump flow at 3500 kPa (507 psi)
−	Pump flow at 10000 kPa (1450 psi)
	Flow loss

Determine the percent of flow loss.

Show/hide table

Table 6
Method of determining percent of flow loss
Flow loss (L/min or US gpm)	×	100	=	Percent of flow loss
Pump flow at 3500 kPa (507 psi)

If the percent of flow loss is greater than 5 percent, replace the pump.

Bench Test

The bench test should be run at full pump rpm in order to determine the percent of flow loss.

If the bench test cannot be run at full pump rpm, run the pump shaft at 1000 rpm. Measure the pump flow at 3500 kPa (507 psi) and at 10000 kPa (1450 psi). Use these values in the formula in Table 7. Run the pump shaft at 2000 rpm. Measure the pump flow at 3500 kPa (507 psi). Use this value in the formula that is in Table 8.

Show/hide table

Table 7
Method for determining flow loss
	Pump flow at 3500 kPa (507 psi)
−	Pump flow at 10000 kPa (1450 psi)
	Flow loss

Show/hide table

Table 8
Method of determining percent of flow loss
Flow loss (L/min or US gpm)	×	100	=	Percent of flow loss
Pump flow at 3500 kPa (507 psi)

If the flow loss is higher than 5 percent, the pump is not functioning correctly.

Pump Flow Test for the 432E, 434E, 442E and 444E Backhoe Loaders

Show/hide table

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

For any pump test at a given rpm, the pump flow at 690 kPa (100 psi) will be larger than the pump flow at 6900 kPa (1000 psi). The difference between the pump flow of the two operating pressures is the flow loss.

Show/hide table

Table 9
Method for determining flow loss
	Pump flow at 690 kPa (100 psi)
−	Pump flow at 6900 kPa (1000 psi)
	Flow loss

Show/hide table

Table 10
Example of determining flow loss
	99 L (26 US gal)
−	95 L/min (25 US gpm)
	4 L/min (1 US gpm)

The flow loss is used to measure the pump performance. Flow loss is expressed as a percent of pump flow.

Show/hide table

Table 11
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)

Show/hide table

Table 12
Example of determining percent of flow loss
4 L/min (1 US gpm)	×	100	=	4%
99 L (26 US gal)

Machine Test

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 to determine the flow loss.

Show/hide table

Table 13
Method for determining flow loss
	Pump flow at 690 kPa (100 psi)
−	Pump flow at 6900 kPa (1000 psi)
	Flow loss

Determine the percent of flow loss.

Show/hide table

Table 14
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)

If the percent of flow loss is greater than 5 percent, replace the pump.

Bench Test

The bench test should be run at full pump rpm in order to determine the percent of flow loss.

If the bench test cannot be run 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 formula in Table 15. Run the pump shaft at 2000 rpm. Measure the pump flow at 690 kPa (100 psi). Use this value in the formula that is in Table 16.

Show/hide table