HYDRAULIC SYSTEM MAINTENANCE: BEST PRACTICES TO MAXIMIZE PERFORMANCE

HYDRAULIC SYSTEM MAINTENANCE: BEST PRACTICES TO MAXIMIZE PERFORMANCE

WHY HYDRAULIC SYSTEM MAINTENANCE IS CRUCIAL

Unlike other mechanical systems, hydraulics rely on a pressurized fluid. This fluid does more than just transmit energy: it lubricates internal components, protects against corrosion, reduces wear on parts, and dissipates heat.

Over time, hydraulic oil degrades. Additives wear out, viscosity changes, and contaminants can accumulate. The result is accelerated wear of components such as pumps, valves, and cylinders.

CHOOSING THE RIGHT HYDRAULIC OIL

Not all hydraulic oils are equal. The choice of the right type depends mainly on operating conditions and climate. According to McNeilus specifications, three grades are recommended:

• ISO 32 OIL: Used in cold climates. It facilitates fluid circulation when temperatures are low. (SUS=40–45 @ 210°F)

In Quebec, where temperature variations are significant, ISO 32 oil is often the best compromise to ensure good performance year-round. The McNeilus technical specifications for this oil are: viscosity at 40°C of 31.7 cSt, viscosity at 100°C of 5.3 cSt, recommended viscosity index of 98, and pour point of -38°F (-39°C).

ESSENTIAL ADDITIVES

A high-quality hydraulic oil should contain the following additives:

• Anti-wear
• Anti-corrosion
• Anti-oxidation
• Anti-foaming

These additives help maintain the stability of the hydraulic system and reduce the risk of failure.

SERVICE INTERVALS: A CRITICAL DISCIPLINE

Hydraulic oil does not last forever. Even if it appears clean, its chemical properties deteriorate over time. It is recommended to follow a precise schedule based on:

• Number of operating hours
• Operating conditions
• Manufacturer recommendations

McNeilus recommends replacing hydraulic oil and filters after 100 hours of use on a new vehicle and then every 1250 hours (without a clean fill system).

Several factors accelerate oil degradation: system overheating, contamination by water, dust or debris, and oxidation. Delayed replacement significantly increases wear on hydraulic components and the risk of failure.

THE IMPORTANCE OF HYDRAULIC FILTERS

Filters play a key role in protecting the system by capturing particles that could damage internal components.

Four elements must be monitored:

• Return filter
• Reservoir suction strainer
• Reservoir breather
• High-pressure filters (1 or 2, not present on all vehicles)

A visual indicator often mounted on the return filter housing of the reservoir usually allows you to check the filter condition:

• Red: immediate replacement required

Ignoring these indicators can result in contaminated oil circulating through the system and accelerated wear.

PREVENTING CONTAMINATION: THE GOLDEN RULE

Contamination is the main cause of hydraulic system failure. A single particle can damage critical components. Cleanliness is of utmost importance during any intervention on the hydraulic circuit. Contamination can come from:

• Dust and particles
• Water or moisture
• Metal residues
• Poor practices during filling

To limit these risks, certain best practices must be integrated into operations:

USE A CLEAN FILLING SYSTEM

Quick-connect filling systems allow oil to be filtered before entering the tank.

MAINTAIN A CLEAN ENVIRONMENT

Cleaning surfaces around access points before any intervention significantly reduces the introduction of contaminants.

AVOID UNNECESSARY OPENINGS

Every system opening increases the risk of contamination. It is therefore important to limit handling.

REGULARLY CHECK SEALS

Worn seals can allow air or water to enter the system.

MONITORING OIL LEVELS, TOPPING OFF, AND DETECTING ISSUES

An improper oil level can lead to performance loss and serious damage.

OIL LEVEL CHECK PROCEDURE

To obtain a reliable reading, the system must be in a precise rest position before any check. Certain conditions must be met:

• Oil must reach normal operating temperature
• Pack and ejection in HOME position or fully retracted
• Tailgate in DOWN position
• Top door in OPEN position
• Arms and forks fully raised (HOME position)

Once these conditions are met, the level can be checked using the sight gauges located on each side of the reservoir.

OIL TOP-OFF PROCEDURE

Before adding hydraulic oil, the following steps must be followed:

• Place all hydraulic functions in neutral/rest position
• Ensure cylinders are fully retracted
• Check the oil level in the reservoir

During filling:

• Use oil that meets specifications
• Filter the oil before it enters the system
• Avoid any external contamination
• Level the oil in the reservoir according to recommendations

A simple but rigorous procedure helps preserve fluid quality and ensures stable operation.

DETECTING SIGNS OF WEAR

A hydraulic system losing performance generally shows visible signs:

• Reduced lifting power
• Irregular movements
• Unusual noises
• System overheating
• Slowing of functions

These indicators must be taken seriously. A quick intervention often helps avoid more significant repairs.

ADOPTING DAILY BEST PRACTICES

Maintenance is not limited to scheduled intervals. Daily habits make all the difference. Structured hydraulic system maintenance allows you to:

• Ensure operational continuity
• Reduce repair costs
• Increase equipment lifespan
• Improve operational safety

At L’Arsenal, we support organizations in implementing maintenance practices tailored to their operational realities.

CONCLUSION

A well-maintained hydraulic system means a more efficient, reliable, and durable truck. By selecting the right oil, strictly following service intervals, and applying rigorous cleanliness practices, you significantly reduce the risk of failure.

Investing in maintenance is investing in long-term performance.