PISTON-SERVO 1924581 - Caterpillar

Illustration 2 g00382217
Circuit diagram
(1) Swing motor
(2) Connector
(3) Tee
(4) Makeup line
(5) Main control valves
(6) Blade control valve
(7) Delivery line for blade pump
(8) Plug
(9) Portable hydraulic tester (flow meter)
(10) Pressure gauge
(11) Pressure tap
(12) Engine
(13) Multitach
(14) Blade pump
Illustration 3 g00382219
Blade pump
(7) Delivery line for blade pump
(11) Pressure tap (blade pump delivery pressure)
Illustration 4 g00382453
(1) Swing motor
(2) Connector
(4) Makeup line
Illustration 5 g00382492
Portable hydraulic tester (flow meter)
(9) Portable hydraulic tester (flow meter)
(13) Multitach
(15) Valve Preparation
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 flow meter tool layout and the circuit diagram. Refer to Illustration 1 and Illustration 2.
Disconnect delivery line (7) from blade pump (14).
Install plug (8) and seal (33) to the end of delivery line (7).
Disconnect makeup line (4) from connector (2) at swing motor (1).
Install tee (3) to connector (2) of swing motor (1).
Connect makeup line (4) to tee (3).
Connect portable hydraulic tester (9) between blade pump (14) and tee (3).
Install multitach group (13) on engine (12). This is used to monitor engine speed.
Connect 60000 kPa (8700 psi) pressure gauge (10) to pressure tap (11) of blade pump (14). Test
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.
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.
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).
Turn valve (15) on portable hydraulic tester (9) clockwise until the pump delivery pressure is 20600 490 kPa (3000 72 psi).
Record the pump flow in Table 1.
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 38 (10)(1)
Service limit 29 (7.7)
(1) MinimumNote: 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.
Table 2
Corrected flow = Measured flow x 1800 rpm
measured