Hydraulic hoses and fittings for specialist vehicles

fittings and couplings placed onto hydraulic hoses

Hydraulic hose for the construction, agricultural and mining industries have to be robust and flexible. Hydraulic fittings have to be up to the job, too, but first let’s look at hose types. Of course, there are different types of hydraulic hose, but what they all have in common is this: their pressure capacity dictates how the hose is constructed.

High-pressure hoses are used in the most demanding applications, from backhoe hydraulic systems and hydraulic trenchers to tractor hydraulic hoses and combine harvester hydraulic systems. Medium-pressure hose is also common in off-road applications, but heavy engineering often calls for high-pressure hose.

Anatomy of a hydraulic hose

All hose, whether low-, medium- or high-pressure, consists of the same parts: cover, reinforcement and tubing. The difference between high- and low-pressure hydraulic hose really comes down to the material of the reinforcement. Low-pressure hose usually has a synthetic textile braid, while medium- and high-pressure hose typically have wire braiding, though not always. Some are made of thermoplastic or even textiles.

image of hydraulic hose fitting with cover, tube and reinforcement

Cover: Protects against damage from abrasion, wear and its environment.

Reinforcement: Reinforces the hose structure to stand up to internal and external pressure.

Tube: The plastic or rubber inner lining that carries the fluid.

Hose type and pressure ranges

It helps to break down low-, medium- and high-pressure hose by looking at their operating – better known as working – pressure ranges, which are measured in pounds per square inch (psi). Keep in mind that burst pressure is a different animal. It’s the point at which the hose will burst, and that figure is typically four times the psi. So if you have a hose with a 5,000 psi, its burst pressure is 20,000 psi.


Minimum working pressure

Maximum working pressure

Low pressure


300 psi

Medium pressure

300 psi

3,000 psi

High pressure

3,000 psi

6,000 psi

Extremely or very high pressure

6,000 psi


Spiral hose

High- and extremely high-pressure hoses are reinforced with spiralled, high-tensile steel wire, which winds around the tube in alternating, even-numbered layers to balance pressure and containment forces. High-pressure hoses typically have what’s called a “four wire” reinforcement, while extremely high-pressure hose usually has a six-wire reinforcement. The number of layers of spiral wire actually has to do with the inner diameter (ID) of the hose. If the ID is less than 1 inches, then it will most likely have four layers.

As you might expect, braided hose, made of textiles, is more flexible than spiral hose.

Hose for hydraulic system designs

Below is a range of hydraulic hose commonly used in heavy engineering. We’re focussing on EN and SAE standards. What does SAE stand for in hydraulic fittings and hose? The Society of Automotive Engineers. U.S. based, the SAE is today known as SAE International. There are many hose standards around the world, but by far the ones most widely followed are those of the SAE. While not as common around the world as SAE hoses, EN are European standards. Standards often align with each other. For example, Deutsches Institut für Normung is the German national organization for standardization and also used in Europe. So if you’re in England and looking for a DIN or EN hose – or DIN EN, as it often appears – you’ll usually see the SAE standard code next to the European codes to let you know that it meets SAE standards:


Applicable Standard: DIN EN 855 / SAE 100 R7

Also know that standards are voluntary only. Manufacturers apply the standards to give customers continuity and similarities.

Hydraulic hose types

The construction, agricultural and mining industries rely on these types of hoses.

High-pressure hose

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  • For petroleum- and water-based hydraulic fluids
  • Commonly used in tractors and dump trucks
  • Temperature range: -40˚C to 100˚C
  • Types include:
  • A: two braids of wire reinforcement
  • B: two spiral plies and one braid of reinforcement
  • AT: Same as type A, but cover assembles with fittings and does not have to be removed
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  • Thermoplastic inner tube
  • Used with synthetic and petroleum- and water-based hydraulic fluids
  • Temperature range: -40˚C to 100˚C
  • Used in nonconductive applications, such as construction machinery
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  • Available with four or six alternating layers of spiral and high-tensile steel wire, depending on size
  • Temperature range: -40˚C to 121.1˚C
  • Oil and weather-resistant cover
  • Commonly used in agriculture (harvesting), logging equipment and oil fields
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  • Compact rubber hose ideal for routing in narrow spaces
  • Used with petroleum-based hydraulic fluids
  • Temperature range: -40˚C to 100˚C
  • Ideal as backhoe hydraulic hose, tractor hydraulic hose and forklift hydraulic hose
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  • Spiral piles of steel wires wrapped in alternating directions
  • Oil- and weather-resistant synthetic rubber
  • Temperature range: -40˚C to 100˚C
  • Ideal for construction vehicles and equipment
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  • Demanding medium- to high-pressure applications
  • Enables tight bends
  • High-tensile steel wires
  • Used for water- and petroleum-based hydraulic fluids
  • Temperature range: -40˚C to 100˚C
  • Commonly used in agricultural and construction vehicles
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  • Four layers of spiral steel reinforcement
  • Superior impulse resistance
  • Used for petroleum-based hydraulic fluids
  • Temperature range: -40˚C to 100˚C
  • Perfect for when kick resistance and abrasion resistance is needed
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  • One braid of high-tensile steel wire
  • Used for mineral and hydraulic oil, fuel oil and water-oil emulsions
  • Temperature range: -40˚C to 100˚C
  • Used in road construction, agricultural, mining and oil and gas industries

Medium-pressure hose

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  • Thermoplastic inner tube provides outstanding abrasion and weather resistance
  • Synthetic-fibre reinforcement
  • Temperature range: -40˚C to 93˚C
  • Used in construction equipment, lubrication lines and hydraulic lift equipment
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  • One braid of high-tensile steel wire
  • Temperature range: -40˚C to 121.1˚C
  • Used on forklifts, oil field extraction machinery and construction machinery

What size hydraulic hose do I need?

To determine the hose size your system requires, see our helpful how-to guide: Hydraulic hose sizing nomograph.


What are hydraulic fittings?

These are the components that connect hoses, tubing and pipes in hydraulic designs to pumps, valves, cylinders and other areas of the system. Most hose fittings have a male and female part that form the connection. It’s the hydraulic hose fittings that hold and direct the flow of fluid, prevent leaks and maintain pressure. With different types of hose fittings, you can change the direction of the flow and the elevation of lines.

What are hydraulic crimp fittings?

Crimping is often performed to assemble hose and fittings. This is done using a crimping machine.

Manufacturers provide crimp specifications for hose, which are used to adjust the machine’s setting for crimping diameter. The fitting is lubricated, placed at the hydraulic hose end and put in the machine, which attaches the fitting to the hose.

Can I use fittings and hose from different manufacturers?

No. It might be tempting, but it carries dangerous risks, which in turn leaves you vulnerable to liability. Hydraulic connectors, hoses, crimping equipment, accessories – these are designed by the manufacturer so that they work together. Tolerances are different between manufacturers, so don’t assume these components are compatible. Using fittings from one manufacturer and hose from another can lead to bursting hoses and leaking couplings. Worse, ends can blow off, causing severe injury or even death.

Ensure fittings and hose share the same psi

If a hydraulic system has a 5,000 psi, and that includes spikes, you not only need hose rated at 5,000 psi, but your fittings should be too. The fittings are your system’s weakest link. If your fittings are rated 4,500 psi, but they’re connected to a 5,000-psi hose, then what you have is a 4,500-psi system – and potentially a dangerous situation.

Common hydraulic fittings

Typical hose connector types for specialty vehicles include hydraulic adapters and fittings:


electronic drawing of a hydraulic fitting

Hydraulic adapters

These are not technically hydraulic fittings – though sometimes they can be. Otherwise, adapters enable different component standards, such as SAE, to connect to, for example, JIS b2351 standard. Whatever you’re connecting, remember that you’ll need a high-pressure hose adapter if you’re using high-pressure applications.

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Hydraulic hose couplings

What is a hose coupling? It’s a good question because couplings are synonymous with fittings. They join together hose with other parts of the hydraulic system. They’re available as permanent or reusable, also called field-attachable.

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Normally, only high-pressure hose uses field-attachable couplings, given that industries such as construction operate outside, without access to a crimping machine.

Permanent couplings are generally more reliable than reusable high-pressure hose fittings. Attaching these couplings in the field only requires a wrench and vise, but it is a more time-consuming process than attaching permanent hydraulic coupling fittings.

Hydraulic quick coupling types

The construction and agricultural industries must be able to connect and detach hoses from cylinders, pumps and manifolds on a frequent basis. Quick couplings enable the user to do this with convenience and speed. No tools are needed and the couplings self-seal when released. When connected, male and female couplings form a fluid-tight seal to avoid fluid spills.

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Types are male couplings, called plugs.

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Their female counterparts, known as sockets.

electronic drawing of a hydraulic tee fitting

Hydraulic tee fitting

Commonly used in agricultural applications, these connect three flow sections in a T-shaped intersection, enabling fluid to split apart, or combined, as needed.

Sizing your fittings

To ensure the integrity of the pressure-holding capacity and seal reliability, you need to size your fittings and any adapters correctly. If you’re using SAE hose, use SAE fittings from the same manufacturer. You’ll find charts for all thread standards and sizes, along with a step-by-step guide on how to measure in Identifying threads and connectors.

While not specific to specialty vehicles, you can also learn more about fittings in general in Your hydraulic fitting: which should you choose and why?


Download free CADs and try before you buy

Free CADs are available for most solutions, which you can download. You can also request free samples to make sure you’ve chosen exactly what you need. If you’re not quite sure which solution will work best for your application, our experts are always happy to advise you.

Whatever your requirements, you can depend on fast despatch. Request your free samples or download free CADs now.


Email us at sales@essentracomponents.com or speak to one of our experts for further information on the ideal solution for your application 800-847-0486.