GENERATOR GP-HYDRAULIC 1787237 - Caterpillar

Table 1
REQUIRED TOOLS
Part Number Description Qty
177-7861 Hose 2
6V-4143 Coupler Assemblies 4
8T-0855 Pressure Gauge 0 to 4000 kPa 2
6V-3989 Unvalved Nipple 2
7X-2444 Tee 1
6V-3965 Nipple 1
6V-5049 O-Ring Seal 1
3J-1907 O-Ring Seal 1
Personal injury or death can result from escaping fluid under pressure.Escaping fluid under pressure, even a very small pin-hole size leak, can penetrate body tissue and cause 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.Always use a board or cardboard when checking for a leak.
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.
Before any tests are performed, prepare the machine for troubleshooting. Refer to Testing and Adjusting, "Machine Preparation". Before any tests are performed, visually inspect the machine for oil leaks and damaged parts. Refer to Testing and Adjusting, "Visual Inspection".Note: The oil in the hydraulic system must be at an operating temperature of 45° 5°C (113° 9°F). This temperature range is specified for standard factory fill oil only. Use the Electronic Technician Software to monitor this temperature. Or refer to Testing and Adjusting, "Hydraulic Oil Temperature Test" for an alternate procedure.The pilot system pressure test determines the pilot control pressure to the electrohydraulic controls. The pilot oil is supplied by the charge pump section of the gear pump. This test is performed to determine if the control pressure that is supplied to the work tool control valve is within the specification.
Engage the parking brake. Stop the engine.
Release the hydraulic system pressure. Refer to Testing and Adjusting, "Hydraulic System Pressure - Release" for the correct procedure.
Block the tracks/tires of the machine.
Raise the cab.
Illustration 1 g06005684
(1) Charge pressure test port
Install one 8T-0856 Pressure Gauge to the charge pressure test port (1) with one 177-7861 Hose.
Illustration 2 g06005692
Standard flow
(2) Pressure test port for the pilot system pressure test
Illustration 3 g06005730
High flow
(2) Pressure test port for the pilot system pressure test
Install the remaining 8T-0856 Pressure Gauge and the 177-7861 Hose As to the pilot pressure test port (2) on the electrohydraulic operated control (work tool).
Secure the two hydraulic lines so that the pressure gauges can be viewed by the operator during the test. The hoses should not be pinched when the cab is lowered.
Lower the cab.
Sit in the operator seat. Fasten the seat belt and lower the armrest.
Start the engine. Disengage the parking brake.
Run the engine at LOW idle. Record the charge pressure and the pilot pressure.
Run the engine at HIGH idle. Record the charge pressure and the pilot pressure.
Table 2
PILOT SYSTEM PRESSURES for All MACHINES
Pilot Pressure Low Idle High