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What are Hydraulic Fittings?

Hydraulic fittings are used in a hydraulic system to connect hoses, valves, pipes and tubes. They fulfill two main functions: holding and sealing. They help contain hydraulic fluid so none escapes the system, and also help direct flow and maintain system pressure.

Since a hydraulic system operates in high pressure environments, hydraulic fittings must meet strict design standards. They must be durable, reliable, strong and corrosion resistant. Therefore they are most often made from high resistance metals such as aluminium, brass, steel and stainless steel. Different materials are optimal for different environments. Often a fitting should be a similar material to the components it is connecting.

Most fittings create a connection by joining a male component to a female component. The most common method for assembling hoses and fittings is crimping. Specialised crimping machines ensure the connection is solid and sound.

When selecting a hydraulic fitting, the best practice is to use fittings manufactured by the same company as the hose. Care should also be taken when identifying the threads of fittings. It is important these are matched correctly to ensure safe operation.

Different Types of Hydraulic Fittings

There are a vast range of different types of hydraulic fittings on the market. When identifying the type of hydraulic fitting you require, you should consider the following factors: 

  • Permanent vs Reusable

Hydraulic fittings can be either permanent or reusable. Permanent fittings are quick to attach with a crimping machine and are reliable. Reusable fittings aren’t as commonly used these days because they are less reliable and more time consuming to fit.

  • Fitting Ends & Port Connections

To ensure a correct and safe assembly, fittings with the right port connections must be identified. There are many different types of port connections available for a wide range of applications.

  • Sealing Method & Fitting Design

There are many types of hydraulic fittings, but three of the most common are: 


  • O-Ring Fittings – these fittings have an O-ring seal that is usually made of rubber. It is fitted around the male component to prove a leak-proof seal when connected to the female component.
  • Tapered Threaded Fittingsfor these fittings, the male component has threads on the outside and the female component has threads on the inside. When they are threaded together, a seal forms. 
  • Mated Angle Fittingsthese form a seal due to the angle of the male component inside the coupling. 

Within these main categories, there are several variables of fitting design including the location of the O-ring, seat angle and the fitting end type. It is important the correct specifications are selected to ensure optimal function for your specific application. If you are unsure, speak to a hydraulic professional.

  • Fitting Features

Hydraulic fittings often have various features which enable them to perform specific functions required by the application. Some common fitting features include: 

  • Flexible Fittings – which can move without being damaged.
  • Expansion Jointsthese account for movement from heavy loads, shock or high temperatures.
  • Swivelthis allows fitting ends to swivel or rotate. 
  • Connect-under-pressure Fittingsfor when fittings need to be installed under pressure.

At Hydraulic Solutions and Sales, we supply a wide range of high quality hydraulic hoses and fittings. For more information, or to make an enquiry, get in touch with our friendly team today.