GASKET 4Y9941 - Caterpillar

Do not operate or work on this machine or work tool unless you have read and understand the instructions and warnings in the Operation and Maintenance Manuals and Owner's Manuals. Failure to follow the instructions or heed the warnings could result in injury or death. Contact your Caterpillar dealer for replacement manuals. Proper care is your responsibility.
Sudden movement of the machine or release of oil under pressure can cause injury to persons on or near the machine.To prevent possible injury, perform the procedure that follows before testing and adjusting the auxiliary hydraulic system.
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, and the 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.
Care must be taken to ensure that fluids are contained during performance of inspection, maintenance, testing, adjusting and repair of the machine. 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 in Caterpillar machines.Dispose of all fluids according to local regulations and mandates.
Move the machine to a smooth, horizontal location away from operating machines and away from personnel. Note: Permit only one operator on the machine at a time. Keep all other personnel away from the machine or in the sight of any operator.
Engage the parking brake. Place blocks around the wheels.
Stop the engine.
Make sure that all of the hydraulic pressure is released before any hydraulic components are altered. During a diagnosis of the hydraulic system, remember that correct oil flow and pressure are necessary for correct operation. The output of the pump (oil flow) increases with an increase in engine speed (rpm) and decreases when engine speed (rpm) is decreased. Oil pressure is caused by resistance to the flow of oil.Before any tests are made, visually inspect the complete hydraulic system for oil leaks and damaged parts. For some of the tests, a magnet and a measuring rule are usable tools.When any test is made of the machine systems, the hydraulic oil must be at the normal temperature for operation.Troubleshooting can be complex. A list of some of the possible problems and corrections is on the following pages.This list of possible problems and possible corrections will only provide an indication of the location of a problem and the repairs that are required. Remember that a problem is not necessarily caused by one part, but by the relation of one part with other parts. This list cannot provide all possible problems and corrections. Service personnel must find the problem