What precaution should be taken to prevent contamination of hydraulic systems when hydraulic lines have been disconnected?

To prevent contamination of hydraulic systems when hydraulic lines have been disconnected, capping and plugging all lines and fittings is essential. This practice creates a barrier that protects the interior of the hydraulic lines from dirt, dust, moisture, and other contaminants that could cause damage or affect the performance of the hydraulic system when it is reconnected.

Hydraulic systems are designed to operate under high pressure and require clean fluid to function effectively. Contaminants can lead to system failures, inefficient operation, and increased wear on components. By capping and plugging the open ends of lines and fittings, you ensure that nothing can enter the system during the period of disconnection.

Leaving the lines open can expose them to environmental contaminants, while soaking the ends in hydraulic fluid does not guarantee protection and can still allow for some amount of contamination. Cleaning the lines with solvent might remove some existing contaminants, but it does not prevent new contaminants from entering the lines once disconnected. Therefore, capping and plugging is the most effective precaution to maintain the integrity of the hydraulic system.