What specific hydraulic malfunctions are most common in car lifts?

Based on the provided information, the most common specific hydraulic malfunctions in car lifts and other hydraulic systems include:

1. Fluid Contamination (Air and Water): This is cited as a leading cause, accounting for a large percentage of hydraulic failures 3.

• Air Contamination: This can occur as aeration (air entering the system from outside, often through leaks) or cavitation (dissolved air in the fluid imploding under pressure) 36. Aeration can cause a knocking sound, while cavitation often results in a whining noise and can severely damage the hydraulic pump and other components over time 3.

• Water Contamination: Water can enter the system through leaks or condensation due to temperature changes 3. It degrades components through oxidation and can cause freezing damage, and is often identifiable by a milky appearance in the hydraulic fluid 3.

2. Hydraulic Leaks: Leaks are a frequently mentioned issue, leading to low fluid levels and potential system failure 6789. Leaks can occur in lines, connections, seals, or valves 36.

3. Issues with Hydraulic Fluid Level and Quality: Low hydraulic fluid levels can cause a loss of pressure or power and may lead to air contamination 35. Using the incorrect type or viscosity of fluid, or having contaminated fluid, negatively impacts system performance and can cause temperature problems or accelerate wear 3.

4. Temperature Problems: The hydraulic fluid operating outside its recommended temperature range causes malfunctions 3.

• Overheating: High temperatures can thin the fluid, reducing lubrication and increasing leak potential, or cause it to oxidize and thicken, restricting flow 3. Poor heat dissipation is a common cause 3.

• Operating When Too Cold: Low temperatures increase fluid viscosity, making it hard for the pump to draw oil, which can lead to cavitation and damage if the system is put under load before warming up 3.

5. Problems with Hydraulic Valves: Malfunctions or blockages in control valves, relief valves, or bypass valves can prevent the lift from operating correctly 367. This can manifest as the lift not moving, moving slowly or unpredictably, binding, dropping a load, or leaking 367.

6. Hydraulic Pump Issues: The hydraulic pump itself can malfunction, often due to contamination or wear, preventing the system from building adequate pressure 347. Symptoms can include abnormal noises like whining or knocking (often due to air contamination) or a complete failure to lift 3.

These specific malfunctions can lead to observable problems such as lifts lowering too slowly, not raising or lowering, sinking arms, or erratic operation 69.