Skip to content
The Common Causes of Premature Seal Failure in Heavy Equipment

The Common Causes of Premature Seal Failure in Heavy Equipment

A close-up of worn metal components with a pile of rocks sitting on top

The Common Causes of Premature Seal Failure in Heavy Equipment

Reading time: 5 min 30 sec

Introduction to Heavy Equipment Seals

Heavy equipment runs on a complex system of specialized fluids like hydraulic fluid, coolant, DEF, oil and fuel. Seals play a critical role in keeping these fluids contained and preventing the ingress of contaminants from outside of the machine.

When a seal fails, key systems may lose pressure or begin leaking fluids, jeopardizing the safety and operability of the equipment. While seals naturally break down over time, certain adverse conditions may cause seals to fail prematurely.

In this guide, we’ll go over some of the most common factors that contribute to premature seal failure and how to mitigate them. By actively addressing these factors as part of your maintenance plan, you can extend the life of your seals and minimize unnecessary downtime.

Types of Seals and Their Functions

Heavy equipment relies on a variety of seals, each serving a crucial role. Understanding the diversity and functionality of these seals is essential for ensuring equipment longevity and efficiency. Among the many seals used in heavy machinery, a few stand out for their critical roles: hydraulic seals, O-rings, gaskets and dust seals.

Hydraulic Seals 

Hydraulic Seals are used in machinery that relies on hydraulic systems, such as excavators and bulldozers. These seals ensure that hydraulic fluid remains contained within the hydraulic system, preventing leaks that could lead to pressure loss, reduced efficiency or even system failure. Hydraulic seals are designed to withstand high pressure, dynamic loads and harsh conditions.


O-Rings, though small in size, play a vital role in sealing interfaces between parts, preventing the escape of liquids and gasses. Their simplicity and versatility make them indispensable in various applications, from hydraulic systems to fuel handling components. Selecting the correct material for O-rings is critical in order for the O-ring  to withstand the specific chemical and temperature conditions of their application.


Gaskets are used to create a tight seal between two stationary components, such as flanges and joints. They fill the microscopic irregularities between surfaces, preventing leaks of fluids or gasses. Gaskets are crucial in engines and other critical systems, ensuring that the systems function efficiently and without contamination.

Dust Seals

Dust seals protect against external contaminants. They help keep dust, dirt and other particulate matter from infiltrating machinery and compromising the internal components. By preserving the cleanliness of the system, dust seals extend the life of the equipment and maintain its performance.

The Importance of Seal Integrity

The integrity of seals directly impacts the prevention of leaks, maintenance of system pressure and lubrication. 

Leak prevention is a critical aspect of many fluid-based systems. Even minor leaks can lead to significant fluid loss over time, compromising the hydraulic system's efficiency and, ultimately, the machine's operational capacity. 

Ensuring correct system pressure is equally important. When hydraulic system pressure becomes volatile, everything from lifting capacity to the precision of movements is affected. Adequate lubrication, facilitated by intact seals, minimizes wear and tear on moving parts.

When sealing components are compromised, the consequences can be significant such as potential downtime that stalls construction projects. Downtime results in the direct costs associated with repairs but also indirect costs through delays and lost productivity. 

In scenarios where equipment reliability is compromised due to failed seals, the safety risks escalate, posing threats to operators and impacting the overall project timeline.

Common Causes of Seal Failure in Heavy Equipment

Seal failure in heavy equipment can be a complex issue with several underlying causes. Understanding these causes is crucial for preventing downtime and ensuring the longevity of your equipment.

Material and Manufacturing Issues

The compatibility between seal materials and the fluids they come into contact with is extremely important. Using seals made from materials not suited to the hydraulic fluid or lubricants in the machine can lead to chemical degradation, swelling or hardening. This, in turn, can result in leaks, compromised functionality and eventual seal breakdown. 

Additionally, manufacturing defects such as uneven surfaces, incorrect sizing or material impurities can severely diminish a seal’s effectiveness and lifespan. These defects may not be immediately apparent but can lead to catastrophic failures under operational stresses.

Human Errors and Operational Practices

Installation errors represent a significant cause of seal failure. The use of inappropriate tools can damage seal surfaces, while selecting the wrong size or type of seal for a specific application can prevent it from functioning correctly under pressure. 

Furthermore, neglecting routine maintenance—such as failing to clean systems or replace seals at recommended intervals—can lead to accumulation of dirt and debris, causing seal wear or failure.

Environmental and Operational Conditions

Seals are designed to operate within a specific range of temperatures and pressures. Extreme temperatures can cause seals to become too brittle or too soft, leading to cracks, deformation and eventual failure. 

Excessive or uneven pressure, on the other hand, can overstress seals, leading to rupture and leakage. Particulate and water contamination within hydraulic fluid can accelerate seal wear through abrasion and corrosion, significantly reducing seal life.

Influence of Other Components

The condition and alignment of machine components play a crucial role in seal longevity. Misaligned, worn or improperly installed parts can increase stress on seals, causing uneven wear and premature failure. Particulates in the fluid, aside from directly wearing down the seal, can also damage the smooth surfaces against which the seal operates, creating additional points of failure.

Best Practices to Prevent Seal Failure

To avoid premature seal failure and extend the lifespan of heavy equipment, adopting best practices is crucial. The most important among these is the proper selection of seals, which involves choosing materials compatible with the hydraulic fluids, temperatures and pressures they will encounter.

Regular system maintenance is another key aspect of preventing seal failure. This includes routine inspections for wear and damage, cleaning systems to remove contaminants, and ensuring that hydraulic fluids are kept free of particulates and water. These practices help maintain the integrity of seals and prevent the accumulation of damaging debris.

Operational practices can also impact seal longevity. Operating machinery within recommended temperature and pressure ranges is necessary to avoid overstressing seals.

Final Thoughts

Regular seal maintenance is an important aspect of keeping your equipment operational. By keeping your machine’s seals properly maintained, you can reduce downtime, minimize operational costs and help ensure the safety of your operators.

The EquipmentShare shop has dedicated collections of seals, including specific collections for O-rings and gaskets. Our growing parts catalog makes it easy to quickly get the seals you need. Don’t see exactly what your machine needs? Reach out to our dedicated parts experts and get personalized assistance.

Back to Machine Maintenance

Are you signed up for our newsletter?

We'll send you a monthly email covering everything from specialty parts to machine overviews, packed with tons of knowledge from our industry pros and no filler.


Building Blocks Blog


Shop Gaskets Icon


Shop Seals and O-Rings Icon


Previous article Best Practices for Charging Lithium Ion Batteries in Construction Equipment
Next article The Effects of Worn Tracks on Heavy Equipment Performance and Safety