Forklift O-rings: Why Do they Need Replacing?

Reading time: 4 min 32 sec.


O-Rings can be found in many forklift parts, and they are used for various purposes and might be compromised in different ways. Some O-Rings might wear over time, and some others get damaged when the forklift is operated in extreme conditions or when it has been poorly maintained. The following blog will look at common causes of forklift o-ring failure, how they can be prevented and what to do when they fail.

Table of contents

  1. Forklift O-Rings
  2. What is the purpose of an O-Ring?
  3. How to measure an O-Ring?
  4. Is O-Rings a gasket?
  5. Common causes why a forklift O-Ring should be replaced
  6. Here at Lift Parts Warehouse we count on a great variety of O-Rings
  7. Takeaways

Forklift O-Rings

The O-Ring is a simple mechanical component that withstands vacuum and prevents oil from leaking in forklifts. In the hydraulic system, the working fluid is sealed by O-Rings in the pressurized regions that allow lifting and lowering actions of a forklift.

This O-Ring is commonly black rubber made from a great oil and heat-resistant material. These have physical properties similar to natural rubber but superior chemical resistance, a better compression set, and no stick-slip effect.

Forklift O-Rings
Set of Forklift O-Rings

What is the purpose of an O-Ring?

The function of forklift O-Rings is to seal the cylinders and pistons that allow lifting and lowering movements. This kind of product is commonly found inside pneumatic cylinders and hydraulic pistons of forklift attachments such as forks, scissor hoists, rotating drums, loading arms, etc. Check our blog about Forklift Hydraulic Cylinders.

Regular maintenance is encouraged to inspect all seals and replace them when they leak oil. It is also recommended to check piston ring tension and their clearances in the cylinder bores.

How to measure an O-Ring?

The O-Rings are also commonly used in industrial and commercial applications. To ensure that an O-Ring functions properly, it is essential to measure it correctly. There are two standard methods for calculating O-Ring dimensions: the inside diameter (ID) and the cross-section (CS).

The ID of an O-Ringis the measurement of the inner diameter of the ring. To measure the ID, use a caliper to measure the distance between the two points on the ring farthest apart. The CS of an O-Ring is the measurement of the width of the ring.

Cross-section (CS) diameters range from 0.040 to 0.275 inch. Inside Diameters ( ID) range from 0.029 to 25.940 inches. The outside diameter (OD) can be calculated with the equation 2CS + ID = OD.

 internal diameter and cross section of an o-ring
View of internal diameter and cross-section of an O-Ring

Is O-Ring a gasket?

O-ring and gasket sealing is similar because they both create a seal. However, O-Rings are more versatile than gaskets, given that they can be used under compression or to seal fluids or gasses under pressure. On the other hand, gaskets are more disposable than O-Rings because no moving forklift parts are involved with the seal.

O-rings and gaskets are both seals, but they serve different purposes. O-rings seal pressure or liquids in a limited space as part of a hermetic seal. Gaskets do not have this ability to form a vacuum seal, so they're usually used between two non-porous surfaces.

An O-Ring is a torus-shaped elastomeric sealing device. It's typically used in compression, but it can also be used to seal liquids or gasses under pressure. The O-Ring shape creates a hermetic seal, so there are no moving parts between the ring and whatever else it is pressed against.

A gasket is a material that is usually made of metal, rubber, or paper. It is put into a groove on two surfaces to prevent leakage through the joint. Gaskets are generally used between non-porous objects because the seal relies entirely on compression.

Common causes why a forklift O-Ring should be replaced

Damage to the forklift O-Rings can be caused by moisture, heat, contaminants, shock loading, lack of lubrication. While the damage is usually not severe enough to require immediate replacement, it can cause decreased lifespan, and the O-Ring should be replaced at shorter intervals. The common causes why an O-Ring must be replaced are:

  • The first sign of trouble is usually an explosive decompression. The O-Ring will be removed, and there may also be small blisters on its surface from being overheated or burnt by hot gas during expansion after installation, but this can vary depending upon how long it's been since they were last repaired.
  • High-pressure gas can cause damage to an O-Ring if it's exposed for too long at high temperatures. When this happens, the polymer fluid inside may absorb some of that extra volume and create blisters on its surface, leading us into cracks as pressure drops due to their expansion with the surrounding air.
  • The effects of ultraviolet light on an elastomer material can be destructive. Short wavelength UV rays have high energy, which interacts with the molecular structure and causes cleavage in polymer chains leading to cracking on the surface before leaking or premature failure occurs.
  • Abrasion is a common cause of failure in dynamic applications. The repeated contact between the O-Ring surface and housing creates excessive friction, exacerbated by poor lubrication or an uncoated metal finish on forklift parts that come into contact with them for extended periods.
  • During dynamic applications such as hydraulic rod and piston seals, extrusion or nibbling of the O-Ring can cause a failure. In some cases, this may happen in static systems with high pressure pulsing where clearance gaps open up, trapping them between surfaces that are supposed to match together perfectly at all times.
A damaged Forklift O-Ring
A Forklift O-Ring damaged

Here at Lift Parts Warehouse we count on a great variety of O-Rings

We carry the 17937-Y4400 O-Ring, an ideal replacement for your old one. This O-Ring is made of high-quality materials and is built to last. Our 100% satisfaction guarantee also backs it, so you can be sure you're making a wise purchase.

The16349-18V00 model it's made from high-quality materials for long-lasting use. Plus, our prices are unbeatable, so you can shop with confidence, knowing that you're getting the best value for your money.

Nissan 16618-GX11A is a part designed to fit perfectly on your forklift, so you can rest assured that it will provide long-lasting performance.

These are only a few options from Lift Parts warehouse wide catalog. We offer a one-year limited warranty on all of their products. This guarantee ensures that you are getting the best possible products from the best forklift parts supplier.


  • O-rings are a simple mechanical component that seals fluids from leaking as they work inside the forklift's pressurized lever system.
  • The O-Ring can be measured by either the inside diameter or cross-section, and it is important to measure it correctly in order for the ring to function correctly.
  • O-rings are seals that work with the sealing of pressure or liquids in a limited space, whereas gaskets do not have this ability.
  • If an O-Ring is exposed to high-pressure gas for too long, the polymer fluid inside may absorb some of that extra volume and create blisters on its surface, which leads us into cracks as pressure drops due to their expansion with the surrounding air.