CONTROL-POWER SUPPLY 2226471 - 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 should be the first step for diagnosing a problem. Make sure that the pressure in the system is released before any components are removed. Visually inspect the system in the following manner:
Check the hoses and the lines for wear and for cracks.
Check for the following restrictions in flow: severe bends, clamps that are not installed correctly, damage to hoses and damage to lines.
Check for loose connections.
Check for damage to the components. When you are defining a problem with the air system and/or with the brakes, first perform the steps in Testing and Adjusting, "Visual Inspection". If you complete the visual inspection and the problem has not been identified, perform the steps in Testing and Adjusting, "Operational Checks". If you are still uncertain of the problem, perform the steps that are in the subsection for Testing and Adjusting in this book.