ADAPTER 4742585 - Caterpillar

Do not check for leaks with your hands. Pin hole (very small) leaks can result in a high velocity oil stream that will be invisible close to the hose. This oil can penetrate the skin and cause personal injury. Use cardboard or paper to locate pin hole leaks.
A visual inspection is the first step of troubleshooting. Park the machine on a hard level surface. Move the implement controls to HOLD. Turn the engine start switch OFF. Engage the parking brake and chock the wheels. Ensure that the boom is retracted and that the work tool is resting on the ground.
Check the level of the oil in the hydraulic tank.
Inspect all wiring harnesses for damage or for poor connections. Check the wires for signs of chafing.
Inspect hydraulic components for leaks or for damage.
Inspect all hydraulic lines and connections for damage and for leaks. Check the hydraulic lines for signs of chafing.