Cleaning and Replacing the Oil in a Hydraulic System

In order to provide the most comprehensive support possible, Terex Utilities regularly releases Tech Tips. Tech Tips cover the most common questions that are asked by technicians when they call our Product Support team. Two Tech Tips released in early 2024 cover the procedures to follow when cleaning or replacing the oil in a hydraulic system.

Inspections are Key

Inspections – both daily and annually – are essential in ensuring equipment stays operational and reliable across your fleet. One important aspect of an inspection is checking the hydraulic oil of a bucket truck or digger derrick to ensure there is a proper amount and that the oil is in good condition. The hydraulic system may require cleaning or oil replacement due to contaminates from external sources, from the failure of system components, or when filters are not replaced when they are in bypass. Always follow the inspection and maintenance guidelines listed in your machine’s manuals.

Tech Tip 196: Cleaning the Hydraulic System using Filters.

The number of filters in a hydraulic system will vary. Pilot and radio-controlled units will have a high-pressure filter and a return filter. The high-pressure filter cleans the oil as the oil goes from the pump to the hydraulic control system. When the oil is too cold, the filter may be in bypass until the oil warms up. A return filter removes contamination before it goes back into the hydraulic reservoir. The system can be cleaned using the filters in the system or using a separate filter cart. Remember to have an ample supply of filters on hand to change them as needed.

Visit Tech Tip 196 to find out more on how to clean the hydraulic system.

Tech Tip 197: Replacing Oil in a Hydraulic System

After inspection, technicians may find that the hydraulic system oil needs to be replaced. Causes could be from a variety of factors, such as the change in oil viscosity as the equipment is used in different climates or the oil was contaminated with water. It’s important to remember that if the system has run for an extended period of time with severe contamination without changing filters, then a full disassembly and flush may be required.

Visit Tech Tip 197 to find out more on how to replace oil in a hydraulic system.