FAN AS- 2673989 - Caterpillar

Personal injury can result from hydraulic oil pressure and hot oil.Hydraulic oil pressure can remain in the hydraulic system after the engine has been stopped. Serious injury can be caused if this pressure is not released before any service is done on the hydraulic system.Make sure all of the attachments have been lowered, oil is cool before removing any components or lines. Remove the oil filler cap only when the engine is stopped, and the filler cap is cool enough to touch with your bare hand.
Sudden movement or accidental starting of the machine can cause personal injury or death to persons on or near the machine.To prevent personal injury or death, perform the following:Park the machine on a smooth, level surface.Lower the work tool to the ground and engage the parking brake.Stop the engine and remove the key.Block the wheels and install the steering frame lock.
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.
ProblemThe pump makes noise and the cylinder rods do not move smoothly. There are also air bubbles in the oil.Probable Cause
The viscosity of the hydraulic oil is incorrect.
The relief valve opens below the correct relief valve pressure setting.
There is a loose connection of the oil line on the inlet side of the pump.
The pump is excessively worn.ProblemThe hydraulic oil is overheating.Probable Cause
The viscosity of the hydraulic oil is incorrect.
The relief valve opens below the correct relief valve pressure setting.
The pump is excessively worn.
There is a restriction in an oil passage.
The load of the system is too high.
The oil level is low.
There is a high pressure oil leak in one or more circuits.
The oil is very dirty.
Air is in the hydraulic oil.Note: If the problem is because of air in the oil, the problem must be corrected before the system will operate at normal temperatures. There are two causes for air in the oil.
Return oil that flows to the tank is flowing into the tank about the level of reserve oil in the tank.
There are air leaks in the oil suction line between the pump and the hydraulic tank.ProblemThe pump output is low.Probable Cause
The oil level is low.
The viscosity of the hydraulic oil is incorrect.
The pump is excessively worn.ProblemOil pressure is low.Probable Cause
The relief valve opens below the correct relief valve pressure setting.
The pump is worn.
There is a O-ring that has failed in the system.
The control valve and the valve spool are excessively worn.ProblemThe attachment moves with the control lever in the HOLD position.Probable Cause
The control valve and the valve spool are excessively worn.
A piston seal in a cylinder is excessively worn.
There is a leak in a connection between a control valve