Hercules Seals

Hydraulic systems rely on precision sealing to maintain pressure, control movement, and prevent contamination. When seals begin to fail, performance drops fast — leaks develop, cylinders drift, and downtime becomes unavoidable.

At Union Hydraulics, we supply dependable hydraulic seal kits designed to restore your equipment to proper working condition quickly and efficiently. Whether you're servicing heavy construction equipment, agricultural machinery, industrial presses, or mobile hydraulic systems, we help you get the right kit the first time.

What Is a Hydraulic Seal Kit?

A hydraulic seal kit is a complete set of replacement seals and wear components used to rebuild a hydraulic cylinder. Instead of sourcing individual seals separately, a kit provides all the necessary sealing elements required for a proper repair.

A typical hydraulic seal kit may include:

• Rod seals
• Piston seals
• Wiper (dust) seals
• Wear rings
• O-rings and backup rings
• Static and dynamic seals

Each component plays a specific role in maintaining pressure, preventing fluid bypass, and protecting internal parts from contamination.
When one seal fails, the entire system can be compromised. Replacing the full kit ensures balanced performance and longer service life.

Hydraulic Seal Kits – Quick Overview

• Designed to rebuild hydraulic cylinders
• Restore pressure and eliminate leaks
• Reduce equipment downtime
• Protect internal components from contamination
• Extend equipment lifespan
• Available for industrial and mobile hydraulic systems

Signs Your Hydraulic Cylinder May Need a Seal Kit

Hydraulic seals wear down gradually. Catching the issue early can prevent expensive internal damage.

Common warning signs include:

• Visible hydraulic fluid leaks
• Cylinder drifting or sagging under load
• Reduced lifting or pushing power
• Jerky or inconsistent movement
• Contamination inside the cylinder
• Excessive heat or pressure loss

If you’re seeing any of these symptoms, it may be time for a rebuild.

How to Identify the Correct Hydraulic Seal Kit

Choosing the right seal kit is critical. Using the wrong size or material can cause immediate failure.

To identify the proper kit, you typically need:

• Cylinder bore diameter
• Rod diameter
• Seal groove dimensions
• Equipment make and model
• Original part number (if available)

Seal material also matters. Depending on pressure, temperature, and hydraulic fluid type, seals may be made from:

• Polyurethane
• Nitrile (NBR)
• PTFE
• Viton®
• Other engineered materials

If you’re unsure about sizing or material compatibility, call Union Hydraulics. We’ll walk you through it and make sure you get the correct kit.

Applications We Commonly Support

We provide hydraulic seal kits for a wide range of equipment and industries, including:

• Construction equipment (excavators, loaders, backhoes)
• Agricultural equipment (tractors and implements)
• Industrial machinery
• Hydraulic presses
• Lift equipment
• Material handling systems
• Mobile hydraulic systems

Whether you're rebuilding a boom cylinder, tilt cylinder, steering cylinder, or industrial actuator, we can help you source the correct solution.

Why Quality Seal Kits Matter

Hydraulic systems operate under extreme pressure and harsh conditions. Heat, contamination, vibration, and pressure spikes all accelerate seal wear.

A high-quality seal kit helps:

• Maintain consistent pressure
• Prevent fluid bypass
• Protect cylinder walls and rods
• Extend equipment life
• Reduce unplanned downtime

Low-grade seals may fit initially but fail prematurely. Investing in the right kit saves time and prevents repeat repairs.

Installation Best Practices

Proper installation is just as important as choosing the right kit.

Before installing new seals:

• Inspect the rod for scoring or pitting
• Check the cylinder barrel for internal damage
• Clean all components thoroughly
• Replace worn wear rings
• Lubricate seals properly during assembly

Taking the time to inspect and prepare components ensures the new seals seat correctly and perform as intended.

Frequently Asked Questions

How long do hydraulic seals typically last?

Seal life depends on pressure, contamination levels, temperature, and workload. Heavy-duty applications may shorten seal lifespan due to constant stress and heat.

Can I replace just one seal instead of the entire kit?

While possible, replacing the complete seal kit ensures balanced wear and reduces the risk of future leaks.

What causes hydraulic seals to fail?

Common causes include contamination, excessive heat, pressure spikes, improper installation, worn rods, and damaged cylinder walls.

Are seal kits specific to each cylinder?

Yes. Seal kits are designed for specific bore and rod sizes. Using an incorrect kit can cause leaks or immediate failure.

Can Union Hydraulics help identify my seal kit?

Absolutely. If you have measurements, part numbers, or equipment details, call us, and we’ll help you confirm the correct kit.

Why Work With Union Hydraulics?

Hydraulic systems aren’t forgiving. Precision matters.
When you work with Union Hydraulics, you’re working with a team that understands hydraulic systems — not just part numbers. We help you:

• Confirm proper sizing
• Verify compatibility
• Understand material options
• Reduce downtime with the right solution

Our goal is simple: keep your equipment running safely and efficiently.

Not Sure Which Seal Kit You Need?

Don’t guess. The wrong seal kit can cost you time, fluid, and productivity.
Call Union Hydraulics and tell us what you're working on. Share your measurements, equipment model, or part number, and we’ll help you determine the correct hydraulic seal kit quickly and accurately.

We’re here to make sure you get back to work without unnecessary delays.