Differentiating Between Different Types of Hydraulic Hose Fittings and Assemblies

Unlike pneumatic hose fittings, hydraulic fittings are used to connect two hose pipes that are used for the transfer of fluids for the smooth functioning of a piece of machinery. Depending upon the type of connection, a hydraulic fitting can be classified into different categories. The following should help you to differentiate

between the several types of hydraulic hose assemblies and fittings.


O-ring seals are commonly used in hydraulic system fittings. These fittings have some threads screwed into the hose pipe providing a secure connection. They are likely to have face seal, flat-faced, or flange type fitting. These rings are designed to sustain a pressure of around 2500 to 3500 psi. Additionally, O-ring fittings have the following advantages:

  • Simplified design supports the ease of installation and operation
  • A wide range of temperature adaptability
  • Sturdy performance delivers lower cost of ownership
  • Limited maintenance requirements


This type of hydraulic fitting usually has a ferrule body. It tightens on to the fitting nut and compresses the tube in such a manner that it penetrates the outer diameter of the tube and seals it. Flareless hydraulic fittings require less tube preparation and can support about 3000 psi.

Flareless fittings have gained wide acceptance due to the ease of fabrication associated with the fitting due to the lack of tube preparation they require. Further, flareless fittings have established a solid record for reliability which serves to lower maintenance costs and downtime.

Finally, flareless fittings provide exceptional resistance to vibration as a result of the positive seal created by the penetration of the tube itself.


These types of hydraulic hose fittings are available in many different sizes. As the name suggests, the special characteristic of elbow fittings is that both ends of the fittings are connected to the hose at a designated angle.


Flanges have retained their popularity in no small measure because of the simplicity of their design. A typical four-bolt flange design consists of the following parts:

  • Flange Clamp
  • Flange head
  • Four bolts
  • O-ring

When the flange is tightened, the O-ring is compressed in a groove in the flange affecting a seal. This is then locked into place by securing the four bolts.

Flange based connections are frequently employed in demanding applications due to the wide range of benefits that they provide, including:

  • Resistance to loosening in high-pressure applications.
  • Simplify the connection between rigid system components such as tubing or hoses.
  • Facilitate the connection between different hydraulic transport mediums such as tubing to piping


Hydraulic flanges were originally developed as a solution to the need for fittings to deal with large-scale highly pressurized applications. Their basic multiple bolt design facilitates the distribution of high levels of torque across the bolts allowing for their safe use in high-pressure solutions.  

Hydraulic flanges are also well suited to situations requiring flexibility regarding positioning. This fabrication flexibility has obvious advantages for hydraulic applications requiring a variety of angles or turns on their routing

Stainless Steel

These fittings have been gaining in popularity due to their corrosion resistance and ease of maintenance. These properties make stainless steel fittings ideal for hygienic applications such as food and beverage manufacturing.

Seaway Fluid Power has a dynamic staff of specialists who have comprehensive knowledge and experience in hydraulics, machining, fabrication, and heavy equipment repair. The expertise of our specialists gives us a unique advantage over our competitors. As a result, we look forward to providing a true value-added experience to each of our customers. To learn more about us at Seaway Fluid Power or our complete range of products, feel free to browse through our website. You can also call us at 877-302-6283!


Seaway Fluid Power (SFP), was established in 1976. Based in St. Catherines, Ontario, SFPG provides its customers with quality fluid power products and services. SFPG carries an extensive parts inventory of fluid power products such as hydraulics, pneumatics, hose and fittings, stainless steel fittings, instrumentation and compressed air.

"When there’s no time for downtime."

Sea Way Fluid Power Group