Choosing the Right Hydraulic Fitting

Hydraulic fittings can connect a variety of materials, including tubes, pipes or hoses to components such as pumps, valves or cylinders. Combined these components create a leak free system that hydraulic fluid can be transmitted safely. There’s a multitude of fitting configurations and variations to choose from, so designers have the ability to change the direction of flow, split flows and alter the elevation of lines.

What Makes Each Hydraulic Fitting Unique?

There are a large variety of fittings available, including plugs, unions, elbows and crosses. The threads of the connections is what significantly differentiates these fittings. SAE, NFPA and ISO documents can help you distinguish your standard which will help you confirm the diameter and type of thread your fitting has.

The way fittings are connected can be accomplished in numerous ways, including:

  • welding
  • threaded
  • flanged
  • barbed
  • quick disconnect
  • push to connect
  • 37° flare
  • 24° flare
  • staple lock
  • face seal
  • push-fit
  • press fit

If you’re working with a non-flanged fitting, these products will have a gender called male (threads on the outside) or female (threads on the inside) that join together to form a union.

How to Choose Your Hydraulic Fitting

When deciding on which type of fitting to select for your system, there a few important factors to consider including your working pressure, vibration, fitting configuration, desired attachment, size of piping, flow, material of the conductor or component you are connecting to and pricing requirements. Equally as important is the use of a seal. The fluid power industry is slowly converting to elastomeric seals to help prevent leakage, but depending on your application, you must be sure that your seal is compatible with the type of hydraulic fluid flowing through your system. Very few applications will require anything other than Buna Nitrile or Viton.

The majority of fitting types are available in different materials including plastic, brass, copper, steel, stainless steel or specialty materials. Your material selection should be based on the fluid flowing through your hydraulic system as well as ambient conditions. Depending on what is needed for your application, each material will have different performance characteristics. Often times, the first obstacle to tackle is matching your fitting to a similar material to the conductor or component that is being connected to.

Another important component is choosing the geometry of your fitting. Generally, the geometry fitting is described by the alphabet letter the fitting resembles. There are fittings that can change the direction of flow and various increments (45° or 90° elbows [L]), or a swivel that allows two jointed sections the ability to rotate. Fittings can also be found that have the capability to split or combine flows with run or branch tees (T), “wahys” (Y) and crosses (+).

The Importance of Hydraulic Fitting Dash Sizes

Depending on your system, you may need larger or smaller sizes to fit flow demands. Fitting connection size is typically expressed in dimensionless terms representing 1/16 of an inch. For instance, if someone calls out a “-0.6 thread,” they man the size is 3/8 or 6/16 of an inch. A “dash 32” size is a 2 inch connection or 32/16 of an inch. It is crucial to note that there are different connection sizes based on the thread type of the fitting you have.


These are just a few important factors to consider when choosing your hydraulic fitting. Don’t hesitate to contact us here at Bryan Hose & Gasket with the link below for more information!

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