HOSE AS 5E7958 - Caterpillar

At operating temperature, the hydraulic oil is hot and under pressure. Hot oils can cause burns.To prevent possible personal injury, release the pressure in the work tool hydraulic circuit (boom, stick, bucket, and swing), travel circuits, and the hydraulic oil tank at the filler cap before any hydraulic lines or components are disconnected or removed.Remove the filler cap only when the engine is stopped and the filler cap is cool enough to touch.
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 operating any compartment or disassembling any component containing fluids.After collecting all fluids in suitable containers, dispose of all fluids according to local regulations and mandates.
Close the jaws of the work tool. Place the work tool on the ground and shut off the engine on the host machine. Close the ball valves on the host machine in order to prevent excess oil to the work tool.
Inspect the area around the swivel for exterior leakage. If evidence of external leakage from the swivel is present, replace the seals in the swivel. Refer to Service Manual, "Swivel - Disassemble".
Illustration 1 g01960873
Remove the six bolts and the washers that secure cover (1) to the lower housing. Remove the cover. Repeat this step for the other side of the work tool.
Illustration 2 g01960874
Disconnect two hydraulic hoses (2) from the cylinder. Install caps onto the fittings of the cylinders and plug the hoses.
Disconnect hose assembly (3) from the ball valve on the stick. Place the open end of the hose in a suitable container.
Start the engine of the host machine and operate the machine until the hydraulic oil reaches normal operating temperature.
Open the ball valve that is still connected to the work tool. Activate the control that opens the jaws. Observe the open end of hose (3). If there is flow through the hose, the seals of the swivel are faulty. Replace the seals in the swivel. Refer to Service Manual, "Swivel - Disassemble". If there was no flow through the swivel and no external leakage was present, the seals of the swivel do not need to be replaced.Note: If the cylinder cycle times were not within the specifications and the seals in the swivel are sealing properly, the cylinder may be leaking internally.
Reconnect hose assembly (3) to the ball valve.
Remove the plugs from the hoses and remove the caps from the fittings on the cylinder. Reconnect the cylinder hoses to the cylinder.
The air must be purged from the work tool before operation. Refer to Service Manual, "Hydraulic System Air - Purge" for the proper procedure.