Beware of air in hydraulic systems

Problem: Aeration occurs when air contaminates a hydraulic fluid. Symptoms include a banging or knocking noise when it compresses and decompresses as it circulates through the system, foaming of the fluid and erratic actuator movements.

Solution: Air usually enters the hydraulic system through the pump’s inlet. Ensure the pump inlet lines are in good condition and all the clamps and fittings are tight.

Flexible intake hoses can age and become porous, so it is mandatory to replace them from time to time.

Aeration also accelerates degradation of the hydraulic fluid, which in turn can cause overheating, and burning of the seals. Regularly check the condition of the pump shaft seal and, when leaking, replace it.

Mr. O’s thanks go to Dow Corning’s Molykote team for this tip.

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