When replacing a hydraulic unit, what is a key precaution to prevent system contamination?

When replacing a hydraulic unit, a key precaution to prevent system contamination is to cap or plug all lines immediately after disconnection. This is critical because hydraulic systems are sensitive to contamination. If open lines are left exposed, they can easily become contaminated with dirt, dust, or moisture, which can adversely affect the performance and reliability of the hydraulic system once the new unit is installed.

By capping or plugging the lines, you create a barrier that protects the internal surfaces from foreign particles during the replacement process. This proactive measure helps maintain the integrity of the hydraulic fluid and ensures that the system operates effectively after the replacement.

While ensuring all components are new, cleaning the area thoroughly, and using sealing tape on connections are important practices in maintenance and repair, they do not directly address the immediate risk of contamination during the disconnection phase. The most effective action to prevent contamination at that moment is the use of caps or plugs on disconnected lines.