Recognizing Common Hydraulic Problems and Their Underlying Causes
Proactive maintenance focuses on early detection and resolution of issues that could cause hydraulic system failures. There are three primary indicators that can help identify potential problems: abnormal noise, high fluid temperature, and slow operation. Addressing these symptoms early can prevent significant damage.
Abnormal Noise
Unusual noises in Automotive Lift Repair Tampa Florida hydraulic systems are typically caused by aeration or cavitation. Aeration happens when air enters the hydraulic fluid, leading to a banging or knocking sound as the air compresses and decompresses within the system. Additional symptoms include fluid foaming and erratic actuator movement. Aeration can speed up fluid degradation and damage components by reducing lubrication, causing overheating, and damaging seals.
To prevent aeration, ensure the pump’s intake lines are intact, and all fittings are secure. Replace old or suspect intake lines, and maintain proper fluid levels in the reservoir to prevent air from being sucked into the system.
Cavitation occurs when a hydraulic system’s fluid supply cannot meet demand, causing vapor cavities that implode under pressure, producing a knocking noise. Cavitation can lead to metal erosion, fluid contamination, and component failure. It commonly occurs at the pump, often due to a clogged inlet strainer or restricted intake line. To prevent cavitation, ensure intake lines are not restricted and regularly check for clogs.
High Fluid Temperature
Automotive Lift Repair Tampa Florida Hydraulic fluid temperatures exceeding 180°F (82°C) can harm seals and accelerate fluid degradation. Operating a hydraulic system above this temperature range should be avoided. High temperatures usually result from reduced heat dissipation or increased heat load in the system.
To maintain optimal fluid temperature, ensure the reservoir is filled correctly and clear of airflow obstructions. Regularly inspect the heat exchanger and cooling circuit components to ensure they function effectively. Internal leakage in components such as cylinders or valves can also generate heat, so identify and replace any faulty parts.
Both aeration and cavitation also increase the heat load on hydraulic systems, contributing to high fluid temperature. Installing a fluid temperature alarm can help monitor and quickly address overheating.
Slow Operation
A noticeable decline in machine performance, such as slower cycle times, is often the first sign of hydraulic issues. In hydraulic systems, flow determines actuator speed. A loss of flow, often due to internal leakage, results in slower operation.
External leakage, such as a burst hose, is easy to identify, but internal leakage—occurring in pumps, valves, or actuators—can be more difficult to detect. Infrared thermometers can help identify areas of internal leakage by detecting unusual heat patterns. However, in some cases, an Automotive Lift Repair Tampa Florida hydraulic flow-tester may be necessary.
Slow operation and high fluid temperatures are often interconnected. As fluid temperature rises, viscosity decreases, leading to increased internal leakage, which further raises the system’s heat load, creating a cycle that worsens over time.
By proactively monitoring noise, fluid temperature, and cycle times, operators can identify and address conditions that might lead to costly repairs or downtime. Often, these issues can be identified through simple, informed observation.
The Role of Filters in Hydraulic Systems and Their Impact on Pump Performance
The primary purpose of filters in Automotive Lift Repair Tampa Florida hydraulic systems is to maintain the cleanliness of the hydraulic fluid, which is essential for maximizing the service life of system components. However, certain filter placements, such as in the suction line, can have the opposite effect and negatively impact pump performance.
From a filtration standpoint, placing the filter at the pump intake seems ideal. This location benefits from lower fluid velocity, which prevents trapped particles from being disturbed, and avoids significant pressure drops across the filter element, which could push particles through the media. Despite these advantages, the restriction created by the filter in the suction line can reduce pump lifespan by creating a vacuum, which leads to several detrimental effects.
Suction Filters and Their Risks
Automotive Lift Repair Tampa Florida Suction filters, typically 150-micron (100-mesh) strainers, are installed on the pump intake inside the reservoir. These filters can create restrictions, especially at low fluid temperatures when the fluid is more viscous and as the filter clogs over time. The restriction increases the likelihood of a partial vacuum forming at the pump inlet, which can lead to two significant issues: cavitation erosion and mechanical damage.
Cavitation Erosion
When a vacuum forms in the pump intake line, the drop in absolute pressure can cause gas or vapor bubbles to form in the fluid. These bubbles implode when exposed to the high pressure at the pump outlet, sometimes generating collapse pressures exceeding 145,000 PSI. In extreme cases, microdieseling can occur, where the air/oil mixture combusts, producing temperatures as high as 2,012°F. When bubbles collapse near metal surfaces, cavitation erosion occurs, damaging critical components (as seen in Figure 1) and contaminating the hydraulic fluid with wear particles. Prolonged cavitation can lead to severe erosion and eventual pump failure.
Mechanical Damage
A vacuum at the Automotive Lift Repair Tampa Florida pump inlet can also cause mechanical damage due to the tensile forces created by the vacuum itself. In an axial pump, for example, the vacuum can place excessive tension on the piston-ball and slipper-pad socket joint, which is not designed to handle these forces. Over time, or in extreme cases, this can lead to the slipper becoming detached from the piston (illustrated in Figure 2), resulting in catastrophic failure.
In addition, the piston retaining plate, which is responsible for keeping the piston slippers in contact with the swash plate, experiences increased wear when subjected to vacuum-induced forces. If the plate buckles, the slipper can lose contact with the swash plate and be hammered back into place by pressurized fluid, causing rapid damage to the piston slippers and swash plate.
While Automotive Lift Repair Tampa Florida bent-axis pump designs are more resistant to vacuum-related issues due to their more robust construction, they are not immune to tensile failure of the piston stem or retaining plate buckling under high vacuum conditions. In vane pumps, excessive vacuum can cause the vanes to lose contact with the cam ring during inlet, leading to damage when they are slammed back into place under pressure.