What should never be used to check for leaks on a pressurized hydraulic system?

The use of bare hands to check for leaks in a pressurized hydraulic system is not safe and should be avoided due to the potential risks involved. Hydraulic fluid can be under high pressure, and if a leak occurs, it can spray out sharply and cause serious injuries, including injecting fluid into the skin or eyes. This presents both a safety hazard and a health risk, as hydraulic fluids can be toxic or harmful to the human body.

Utilizing tools or techniques specifically designed for leak detection, such as soap solutions to create bubbles at leak points or using your sight and sound to identify leaks, is a much safer approach. These methods allow for the detection of leaks without exposing oneself to the dangers associated with high-pressure hydraulic systems. Therefore, it is essential to prioritize safety by avoiding any direct contact with the system while it is under pressure.