Lint from Cleaning Materials
Lint particles from cleaning materials can cause abrasive damage in hydraulic systems, particularly to tightly fitted moving components. These particles may also lodge in the spaces between seals and surfaces, leading to leaks and reduced efficiency. Additionally, lint contributes to premature clogging of filters.
Particles from External Sources
External particles can enter hydraulic systems through points of contact with the atmosphere, such as refill openings, breather vents, and cylinder rod seals. Common risk areas include the piston rods, which can draw in contaminants. Using appropriate filters, filler strainers, and wiper rings on piston rods can help prevent contamination. Air filters are also used in single-acting actuators to block airborne particles.
Particles Generated During Operation
Contaminants generated during Automotive Lift Repair Tampa Florida system operation can be mechanical or chemical. Mechanical particles result from wear and tear on components like pumps, cylinders, and seals. Older hydraulic hoses can also degrade, shedding particles into the system. These contaminants range in size from large fragments to microscopic particles. Chemical contaminants, primarily caused by oxidation, are generated under high pressure and temperature, exacerbated by the presence of water, air, or metal oxides. Oxidation products, such as acids, sludge, and varnish, can increase fluid viscosity or form sediment.
Foreign Liquids
Water is a common foreign contaminant in Automotive Lift Repair Tampa Florida hydraulic systems using petroleum-based oils. It enters the system through condensation and can disperse into fine droplets, forming emulsions with oil and air. When combined with dust or corrosion particles, water can catalyze the formation of damaging sludge, which underscores the importance of hydraulic fluids with water-separation properties.
Contamination Control
Filters effectively manage contamination during normal operations, but service personnel must minimize contamination during Automotive Lift Repair Tampa Florida maintenance. If the system becomes overly contaminated, the filter element should be cleaned or replaced to maintain system efficiency.
To ensure effective contamination control, the following maintenance and servicing procedures should always be followed:
1. Keep all tools and the work area, including workbenches and testing equipment, clean and free from dirt.
2. Use an appropriate container to collect any hydraulic fluid spilled during component removal or disassembly.
Note: Reusing hydraulic fluid is generally discouraged. However, in large-capacity systems where reuse is allowed, the drained fluid must be stored in a clean container and filtered or strained before being returned to the system.
3. Clean the area around hydraulic lines and fittings with an approved dry-cleaning solvent before disconnecting.
4. Cap or plug Automotive Lift Repair Tampa Florida hydraulic lines and fittings immediately after disconnecting them.
5. Wash all hydraulic components with an approved dry-cleaning solvent before assembly.
6. After cleaning, thoroughly dry the parts and lubricate them with the recommended hydraulic fluid or preservative before assembly.
Note: Only use clean, lint-free cloths for drying or wiping components.
7. Replace all packings and gaskets during assembly.
8. Take care when connecting parts to prevent stripping metal shavings from threaded areas. Install and torque all fittings and lines according to the applicable technical instructions.
9. Ensure that all hydraulic servicing equipment is kept clean and in proper working condition.
Checks for Contamination
If there is a suspicion that a hydraulic system has become excessively contaminated or has operated beyond its maximum temperature, the system should be checked. While filters in most hydraulic systems are designed to eliminate visible foreign particles, hydraulic fluid may appear clean but still be contaminated to an unacceptable level.
Therefore, a visual inspection of the hydraulic fluid alone is not sufficient to assess the total contamination in the system. The presence of large particles suggests that one or more components may be experiencing excessive wear. To identify the faulty component, a systematic elimination process is necessary. Liquid returned to the reservoir can contain impurities from any part of the system, so samples should be taken from the reservoir and various locations within the system.
Fluid Sampling
Automotive Lift Repair Tampa Florida Liquid samples should be collected following the instructions in the relevant technical publications for the specific system and contamination test kit. Some hydraulic systems have permanently installed bleed valves for sampling, while others require disconnecting lines. In either case, a small amount of pressure should be applied to the system while taking samples to ensure that the liquid flows out of the sampling point, preventing dirt and other contaminants from entering. Some contamination test kits come with hypodermic syringes for sampling.
Automotive Lift Repair Tampa Florida Contamination Testing
Several methods can be employed to assess contamination levels in hydraulic fluids. The filter patch test is a common procedure that filters a sample of hydraulic liquid through a special filter paper. The degree of darkening of the paper indicates the contamination level and can be compared to standardized filter disks for assessment. More advanced test kits may include a microscope for precise comparisons.
To check for liquid decomposition, pour new hydraulic fluid into a sample bottle that matches the size and color of the original fluid’s container, and visually compare the colors. Decomposed fluid will appear darker.
In conjunction with the contamination check, a chemical analysis may be necessary, which includes viscosity, moisture, and flash point tests. Since specialized equipment is required for these analyses, samples must be sent to a laboratory for testing by a technician.
Flushing the Automotive Lift Repair Tampa Florida System
If contamination checks reveal impurities or decomposition of the hydraulic fluid, the system should be flushed.
If the hydraulic liquid is contaminated, the hydraulic system must be flushed.
Note: The presence of foreign particles in the hydraulic system may indicate a malfunctioning component that should be addressed before flushing.
Flushing a contaminated hydraulic system should be done according to the relevant technical instructions. Manufacturers typically recommend specific flushing procedures, which can vary by system. One common method includes the following steps:
1. Drain as much contaminated liquid as possible. Some systems have drain valves for this purpose, while others may require disconnecting lines and fittings at low points to remove trapped fluid.
2. Close all connections and fill the system with the appropriate flushing medium. Any hydraulic liquid approved for power transmission systems can be used for flushing.
Warning: Diesel fuel must not be used for flushing hydraulic systems that are in operation due to its poor lubricating properties and potential to contaminate the subsequent hydraulic fluid.