Hydraulic Cylinder: The 7 Basic Components You Need to Know

Hydraulic cylinders haven’t changed much since their introduction in 1795 due to the simplicity of their design. Read about the 7 basic components that make up hydraulic cylinders.
Hydraulic Cylinder: The 7 Basic Components You Need to Know

Hydraulic Cylinder: The 7 Basic Components You Need to Know

Hydraulic cylinders haven’t changed much since their introduction in 1795 due to the simplicity of their design. Read about the 7 basic components that make up hydraulic cylinders. Learn more about the history of the hydraulic cylinder in this article.

The hydraulic cylinder, also known as a linear hydraulic motor. This engineering marvel enables all your heavy engineering vehicles to operate. It enables your employees to complete construction, mining and farming related tasks quickly and efficiently by the application through those machines.

Understanding your equipment gives you an edge over your competitors. You can identify problems and propose solutions, saving you time and money. If any of these parts break or if you need a part, we at Kappa Engineering specialise in all the aspects of hydraulic cylinders.  Whatever your hydraulic cylinder needs, we will be able to help.

Hydraulic Cylinder Barrel

The barrel is designed to contain the pressure of the cylinder. This barrel is made from honed tubes which are made from Cold Drawn Seamless Tubes. This steel has to be suitable to be honed. Honing is an abrasive machining process used to produce a precision and smooth surface on the metal that is being honed. Honing is one of the main processes to manufacture a hydraulic cylinder tube. The inside surface of the tube should have a smooth inside surface, be durable and have a high precision tolerance.

Cylinder Head (End Cap)

The cylinder head, also known as the “blind end”. This part is inside the cylinder barrel and is not exposed to daylight, hence the name. This part encloses the pressure chamber from one end of the cylinder. The cylinder head has the option for an integrated rod sealing arrangement or an option for a seal gland which we will discuss in this article in detail.

Hydraulic Cylinder Base or Gland

This part encloses the pressure from the other end of the cylinder barrel. This part is also referred to as the rod end. This can be identified by an opening where the cylinder rod connects to. The cylinder gland is connected by welding, threading, bolts or tie rods as in the example of our 150 series cylinders. The 150 series cylinder caps are connected by tie rods. The gland is also used as a cylinder mounting component. Examples of these mounting components are the cap flange, gland trunnion and the gland clevis. The gland size is determined by the bending stress resistance required by the hydraulic cylinder.


The piston inside the hydraulic cylinder is used to separate the pressure zones inside the barrel. The piston is machined to fit rubber or metallic seals which can be single-acting or double-acting.  The piston rod is attached through threads, bolts or nuts to transfer the linear motion. Depending on where pressure is applied on either side of the piston will cause the hydraulic cylinder to extend or retract. Applying pressure, for example,  on the cap end will extend the cylinder rod outside of the barrel.

Piston rod

Also known as the cylinder rod. This is made from hard chrome plated cold rolled steel. The rod is attached to the piston and the cylinder head. The piston rod connects the hydraulic cylinder to the machine component that is used to do work. The piston rod is made from hard chrome for its properties to be grounded and polished very well. This ensures a reliable seal which prevents leaks.

Seal gland

The hydraulic cylinder gland is fitted with a number of seals that prevent the pressured oil from leaking past the interface of the cylinder rod and the cylinder head. If you take the option of the seal gland this will give you the advantage of easy removal and replacement of all the seals needed to prevent leaks. The seals within the seal gland are the primary seal, secondary seal, wear bands, wiper, scrapper and the static seal.


The seals used within the seal gland are made specifically according to the cylinder working pressure, speed of the cylinder, operating temperature and the application of the hydraulic cylinder. These are dynamic seals and can be single-acting or double-acting. Hydraulic cylinders used in lower temperature environments use Elastomer seals made from nitrile rubber. If your hydraulic cylinders are used at a higher temperature make sure your seals are made of Fluorocarbon Viton as this is better suited for those temperatures. The wiper and scraper seals are used to eliminate contaminants such as dirt and water which can cause extensive damage to the hydraulic cylinder walls. The wear bands are used to avoid metal to metal contact, which if they are absent, will also cause damage to the cylinder walls.


To learn more about hydraulic cylinders please watch the following:


We trust you have learned something about the hydraulic cylinders that make your construction, agriculture and earth-moving machinery work. Kappa engineering is dedicated to providing the best quality hydraulic cylinders to Africa. 

Order any of our extensive hydraulic cylinder products from Kappa Engineering today. We manufacture hydraulic cylinders with any mounting type or port position you require. We manufacture every component of the cylinder in-house and we design and build custom hydraulics for specialised applications.

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