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Global solutions in hydraulic. Since 1965

Preventive and Corrective Maintenance in Industrial Hydraulic Systems: A Strategic Investment

The Vital Role of Hydraulic Fluids

At the heart of modern industrial machinery, hydraulic systems play an essential role. From heavy construction equipment to precision control systems, their performance depends directly on one often underestimated element: the hydraulic fluid.

This fluid not only transmits power but also reduces wear and friction, dissipates heat, and protects against corrosion. In other words, it is the “circulatory system” of the machinery.

However, hydraulic systems are extremely sensitive to degradation. In fact, contamination—whether internal or external—is responsible for between 75% and 80% of the most common failures. Therefore, rigorously monitoring the condition of both the fluid and the components is not merely a technical task; it is a strategic investment.

Why Is It Crucial to Maintain Hydraulic Systems?

Ignoring hydraulic system maintenance can trigger a chain of costly consequences. Contamination by particles and water affects the fluid’s properties, accelerates oxidation and wear, and ultimately compromises the system’s overall performance.

Main consequences of poor maintenance:

  1. Fluid degradation:
    Water can cause hydrolysis or react with additives, generating acidic and corrosive compounds. Moreover, oil oxidation leads to the formation of sludge, gums, or varnishes that can clog valves and filters.

  2. Component damage:
    Solid particles generated by wear or external contamination act as abrasives, damaging pumps, bearings, and gears. This results in irregular motion, excessive noise, and power loss.

  3. Operational impact:
    A contaminated system shortens component lifespan, causes unplanned downtime, and directly affects the company’s productivity and profitability.

Preventive Maintenance: Anticipating Failure

Preventive Maintenance (PM) aims to extend machinery life and detect issues before they become critical failures. Its foundation lies in cleanliness and hydraulic fluid control.

Contaminant Control: The Essential Routine

Keeping the fluid clean is the most effective action to protect the system. This involves defining cleanliness levels according to international standards (ISO/NAS) and using high-efficiency filtration—e.g., 10-micron or finer filters for standard pressure systems.

Key strategies include:

  • Contaminant exclusion: sealing reservoirs, using desiccant breathers, and pre-filtering all new fluid (ideally with ≤5μm filters).

  • Temperature and viscosity management: keeping the fluid between 49°C and 54°C prevents oxidation and protects seals.

ANAC: Oil Condition Analysis

Oil Analysis (ANAC) is a predictive tool that reveals the health of both the system and the fluid. Through periodic sampling (every 1,000 operating hours on average), parameters such as viscosity, oxidation, water content, and metal particle presence can be assessed.

The results allow for oil change optimization, maintenance planning, and early fault prevention. Ultimately, it’s an intelligent way to turn oil data into strategic decisions.

Corrective Maintenance: Speed and Efficiency

Although preventive maintenance significantly reduces failures, hydraulic systems are not immune to incidents. In such cases, a planned corrective intervention is key to minimizing impact.

  • In-service monitoring: installing pre-set test points enables pressure and fluid quality checks without halting operations.

  • Rapid diagnosis: monitoring results (e.g., “Red” alert codes) facilitate immediate decision-making.

  • Root cause analysis: after each intervention, identifying the failure’s origin helps improve preventive maintenance plans and avoid recurrence.

Tangible Benefits of an Integrated Strategy

Adopting a combined preventive and corrective maintenance approach delivers measurable benefits:

  • Reduced operational costs through planned downtime.

  • Optimized oil consumption, safely extending change intervals.

  • Greater reliability and longer equipment lifespan.

  • Significant savings on major repairs by replacing components before catastrophic failure.