In a hydraulic system diagnostic scenario similar to the one previously described, we’re analyzing a situation where no pressure change is observed after isolating the power supply. This suggests that the issue lies within one or more components inside the power supply itself, rather than downstream in the system. Any of these parts can be responsible for a pressure loss issue, and careful observation and systematic troubleshooting are required to narrow down the root cause.

One of the earliest things you might notice in a failing system is an unusual sound—more specifically, a high-pitched whining noise. This sound can often indicate cavitation, which is a condition where the pump attempts to draw more fluid than is available, leading to the formation and collapse of vapor bubbles. 

The Car Lift Repair Victorville CA suction strainer, typically positioned inside the reservoir and submerged below the oil level, is a component that often gets overlooked. Because it is out of sight, it tends to be neglected during routine maintenance checks. Over time, debris, sludge, or contaminants can clog this strainer, which significantly restricts the fluid flow into the pump. Since a pump cannot output more fluid than it can intake, this blockage can lead to reduced or erratic system flow. However, it’s also possible for flow to drop off suddenly, particularly if turbulence in the reservoir stirs up sludge that then clogs the Car Lift Repair Victorville CA strainer all at once.

Checking the suction strainer is a relatively quick and straightforward diagnostic step. This can be done by removing the suction line and visually inspecting the strainer. If the strainer appears clogged or covered in sludge, it should be removed and cleaned, often with compressed air. After cleaning and reinstalling it, one can then recheck the system to see if the pressure returns to normal. If the sound and performance issues resolve after this step, the problem was likely cavitation due to a plugged strainer. At this time it would be a good idea to have all of your manufacturer’s guidelines laid out in a clear manner that everyone in your shop can easily access and read. Be sure to follow all safety guidelines to the letter when working with parts that tend to be under pressure. Be sure to release all pressure safely in accordance with the guidelines  set forth in your manufacturer’s manuals. 

If no such whining sound is detected, and the pressure remains low, attention should shift to the relief valve. The Car Lift Repair Victorville CA relief valve’s purpose is to limit the system pressure by redirecting excess flow back to the reservoir when the pressure exceeds a certain setpoint. In cases where the relief valve is stuck open, the Car Lift Repair Victorville CA system cannot build or maintain pressure even if all other components are functioning properly. One approach to diagnosing this involves “deadheading” the system—essentially closing a hand valve downstream of the power supply—and attempting to adjust the relief valve. If the valve will not adjust or respond, there’s a strong chance it is stuck or damaged.

Before attempting any internal inspection of the relief valve, it is essential to bleed down residual pressure and ensure the system is fully locked out to prevent injury. Once safely prepared, the relief valve can be removed and examined for issues such as internal contamination, broken or misaligned springs, wear marks, or physical obstructions that could prevent it from seating properly. Particular attention should be paid to orifices within the valve body, as these small openings are critical to the valve’s proper function and can easily become clogged with debris.

A real-world example underscores this point. In one situation, technicians had previously removed and checked the relief valve and reported that two internal orifices had been inspected and found to be clean. However, upon being asked to recheck it, a third orifice—overlooked in the earlier inspection—was found to be obstructed by a very small piece of debris, perhaps the size of a grain of sand. This seemingly insignificant particle was enough to interfere with the valve’s operation. After cleaning this orifice and reassembling the valve, the system pressure returned to normal, proving that even the smallest issues can have a major impact on hydraulic performance.

Another potential culprit is the pump itself. In the Car Lift Repair Victorville CA system under consideration, a fixed-displacement pump is used, and there are effective methods to evaluate its condition. One recommended approach involves using the system relief valve as a diagnostic tool. By installing a flow meter in the tank line of the relief valve, it becomes possible to monitor the flow being returned to the reservoir. This setup works well unless the system design prevents access—such as when the relief valve is directly mounted on or integrated with the reservoir. In such cases, the flow meter can instead be placed in the pressure line leaving the pump.

Care must be taken during this step, as some relief valves lack a mechanical stop on the adjustment screw, meaning the screw could be completely removed if turned too far. 

With the system powered on, and assuming no other flow paths exist, nearly all the pump’s flow should be directed through the relief valve at this low pressure. If the pump is healthy, it should maintain this full flow without issue. Gradually increasing the pressure setting on the Car Lift Repair Victorville CA relief valve allows one to observe how the pump responds under increasing load. A good pump will maintain flow as pressure builds. Conversely, if the flow begins to drop off as pressure increases, the pump likely has internal wear or damage and should be replaced.

In a different scenario, suppose that isolating the power supply by closing the hand valve did cause the system to build pressure. Instead, the issue must lie downstream—most likely within the directional control valve or the cylinder itself. One possibility is that oil is bypassing internally within the directional valve or the Car Lift Repair Victorville CA cylinder, leading to a loss of pressure despite the power supply functioning correctly.