Telescopic Hydraulic Cylinders: 5 Key Benefits

There are many different types of hydraulic cylinders each with its unique functionality. One of the main advantages of using the telescopic hydraulic cylinder variety is the fact that it has a longer stroke compared with other cylinder designs. This cylinder variety is typically used to enhance the functions of process operations.

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If you have operations that are designed to be carried out in a limited or confined space, telescopic hydraulic cylinders are a great option for you. They are also beneficial in places where a longer stroke length is required. But what about hydraulic cylinder repair?

What Is the Telescopic Hydraulic Cylinder?

Telescopic cylinders are also referred to as multi-stage cylinders. They are a variety of linear actuator that consists of tubular rods referred to as sleeves. There are usually four or five sleeves that decrease in diameter and nest inside one another. As soon as hydraulic pressure is exposed to the cylinder, the largest sleeve (called the barrel or main) extends. As soon as the barrel reaches its maximum stroke, the next sleeve (called a stage) starts to extend. This is an ongoing process until the cylinder reaches the final stage that’s referred to as the plunger.

The two types of telescopic hydraulic cylinders include single-acting cylinders and double-acting cylinders. The most common type is single acting which works by using gravity or other external forces to retract the cylinder stages. Once pressure is released, the load’s force pushes oil out of the system and the cylinder retracts.

Benefits

Just like other types of cylinders, there are benefits to using telescopic hydraulic cylinders. We’ve outlined a few of them below.

#1. Telescopic Hydraulic Cylinders Take Less Space

One of the main benefits is the fact that these cylinders can be used effectively in small, compact spaces. If your operations are confined and require compact equipment, consider a telescopic hydraulic cylinder that can extend significantly longer than the collapsed length. This is the most logical option if you have limited mounting space and require a long stroke.

#2. Telescopic Cylinders Can Meet Specific Angle Requirements

Using this cylinder variety is the most practical in vehicles that feature a hydraulic-powered bed such as a dump truck. There are specific angles that are required to gradually release the materials at the required range, requiring a 60-degree angle to empty the contents of the bed. As well as raising the bed, telescoping cylinders are beneficial in collapsing and returning the bed to a horizontal position.

#3. Can be Made as a Constant Thrust / Constant Speed Application

Special telescopic cylinders are known as constant-thrust/constant-speed cylinders. They are configured so that all moving stages extend simultaneously to provide a constant speed and force while it is extending or retracting. This variety of telescopic hydraulic cylinders is often used to drive drill heads in underground mining where performance parameters are necessary. Due to its more complicated design, this type of hydraulic cylinder accomplished the necessary action by internally trapping oil, limiting the number of moving stages, and matching retract and extend areas.

#4. Can be Made as a Double or Single Acting

Another noteworthy advantage is that telescopic hydraulic cylinders can be made as single-acting, double acting, or a combination of the two. If you opt for the combination of single-acting and double-acting telescopic cylinders, you’ll also receive the benefits of a double-acting cylinder combined with the ease of operation and cost-effectiveness of a single-acting hydraulic cylinder.

#5. Telescopic Cylinders Have a Longer Stroke

The stroke length of this cylinder variety is longer than others. The typical collapsed length of a telescopic hydraulic cylinder is roughly 20-40 percent of its fully extended length. This is considered an extra-long stroke that cannot be achieved with other types of cylinder types, making it one of the biggest unique selling points of this variety.

Conclusion

Telescopic hydraulic cylinders are critical to the operation of many types of mobile equipment. They’re commonly found on dump trucks, trailers, refuse trucks, cranes, and agricultural machines. Basically, anywhere a long stroke length is needed in a compact space.

These multi-stage hydraulic cylinders can fail when seals wear out, stages become misaligned, or contamination gets inside the system. When that happens, downtime is costly.

This guide explains how telescopic cylinders work, their key components, common failure points, and how Hercules Sealing Products can help you repair and maintain them using OEM-quality hydraulic seal kits and rebuild kits.

Multi-Stage Extension Design

Each telescopic cylinder consists of multiple nested tubes (or stages) that extend sequentially. This allows a long stroke while still fitting into compact mounting spaces.

Types of Telescopic Cylinders

Telescopic cylinders are available in several designs; each used for different types of equipment.

Single-Acting Telescopic Cylinders

Use hydraulic pressure to extend and gravity (or the equipment’s load) to retract. These are most common in vertical lift applications like dump truck bodies and dump trailers.

Double-Acting Telescopic Cylinders

Use hydraulic pressure to both extend and retract. These are often used in applications like refuse trucks, mobile cranes, and other equipment that requires controlled retraction.

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Key Components of a Telescopic Cylinder

Understanding the main components of telescopic cylinders can help you diagnose issues faster and repair them correctly.

Cylinder Stages (Tubes)

These nested sections extend and retract during operation. Dented or scratched stages can lead to leaks, uneven extension, or premature seal failure.

Rod Gland (Head)

Supports and guides the rod, holding the rod seals and bearings that prevent fluid loss and keep contaminants out.

Base or Mounting Hardware

Secures the cylinder to the machine. Worn or loose mounting hardware can lead to misalignment or damage.

Wipers and Bearings

These components keep hydraulic fluid contained and dirt out. They are the most common items in telescopic cylinders and need regular replacement.

Piston Seals

Separate pressure chambers within the cylinder. Worn piston seals can cause internal leakage, drifting, and reduced lifting power.

Check Out Our Hydraulic Cylinder Repair Parts for all these components. 

Why Telescopic Cylinders Fail

Even the best-built telescopic cylinders will fail if they are not maintained. The most common causes of failure include:

• Leaking rod or piston seals
• Misalignment that causes stage binding
• Contamination from dirt, water, or debris damaging internal parts and seals
• Worn bearings or wear bands that allow excess movement
• Dented or scored cylinder stages

When one part of the system starts to fail, it can quickly cause damage to the rest of the cylinder. Early detection and timely seal replacement is the best way to prevent major failures.

Maintenance Tips to Extend Cylinder Life

Routine maintenance on telescopic cylinders will help you reduce downtime and extend service life. Here’s what to do:

• Inspect stages regularly for dents, scratches, or fluid leaks
• Replace seals, wipers, and bearings at recommended intervals
• Check for misalignment during rebuilds or repairs
• Keep hydraulic fluid clean and replace filters often
• Choose the correct seal material for your system’s fluid, pressure, and temperature

Need help with rebuilding? Check out our Engineer Support.

Custom Seals and Kits for Your Cylinder Needs

When standard seal kits don’t meet your needs, Hercules Sealing Products can manufacture custom hydraulic seals to your exact specifications.

• CNC-machined seals up to 33.5 inches (851 mm) in diameter
• Fast lead times: often as quick as 3–5 business days
• Materials and designs optimized for your application

Learn More About Custom Seals and how they can keep your equipment running.

Why Maintenance Teams Choose Hercules Sealing Products

• Thousands of parts in stock: seal kits, bearings, wipers, and more
• Fast shipping to get your equipment back up and running quickly
• OEM-quality parts designed to perform in the harshest environments
• Real technical support: Our experts know hydraulics and can help you troubleshoot issues fast

Keep Your Telescopic Cylinders Operating Like New

Telescopic cylinders play a crucial role in hydraulic equipment performance. When seals fail or components wear out, it can lead to costly downtime and unsafe conditions.

Hercules Sealing Products has the parts, expertise, and support you need to repair and maintain these cylinders with confidence.

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