How to identify hydraulic hose fittings

Hydraulic hose fittings are essential pieces of equipment which connect hydraulic hoses to other components in a hydraulic system.

If you have worn hose fittings, it’s important to replace these as soon as possible to prevent any leaks or damage to the circuit. But, how do you find the right fitting when there are so many options available – and they all look very similar?

Whilst they may look similar, they all vary in terms of sealing methods and thread types. It’s crucial that you’re able to identify the correct hydraulic hose fitting for the job, and this guide should help you do exactly that.

Follow this fairly straightforward 5-step process to select a compatible fitting for your application.

1. Permanent vs reusable hydraulic hose fittings

The first step in the process is identifying whether your hose requires a reusable or permanent fitting.

More often than not, you’ll be in the market for a permanent fitting. These are typically the most widely used type of fitting used in most modern-day hydraulic systems due to their reliability. Also known as crimped fittings, they require a crimping machine in order to attach and remove them.

On the other hand, reusable fittings only require a wrench and a vice to connect them to a hose. These are more easily identified due to the lack of crimping.

2. Recognise the fitting type and port connections

If you’ve already started looking around for a hose fitting, you may have noticed that there are almost endless options available.

With a vast number of manufacturers all over the world producing hose fittings according to different standards, this leaves us with an extensive list of products which may seem impossible to sift through at first glance.

However, these are categorised and labelled according to their fitting types which makes them easier to identify. Whilst we won’t provide an exhaustive list of every type ever made, here are the most common ones which will likely cover the one you’re looking for:

• BSP/G – British Thread Type fittings are non self-sealing threads. They use either metal to metal angled surfaces, or metal and an O-ring for sealing pipe ends.
• JIC – These are metal to metal American-type fittings which are commonly used in Europe. They are a flare fitting machined with a 37-degree flare seating surface.
• Metric – Uses a basic metal to metal sealing design with a cylindrical internal thread and conical external thread with specific cylindrical diameters inside and out.
• ORFS – O-ring Face Seals are commonly used in high pressure applications. They utilise an O-ring compression mechanism to seal and prevent leakage.
• 4-bolt flange – A worldwide hose fitting type used in high pressure applications with large loads. They incorporate an O-ring sealing and are usually separated into two pressure classes – 3000 psi and 6000 psi.

The next step is to then identify the port connections of your hydraulic hose. It’s crucial to ensure that the port connection of the fitting matches the one on the hydraulic hose.

Here are the most common port connections:

• 37 degree flare
• 30 degree flare (metric)
• 45 degree flare
• 30 degree flare (BSPP)
• O-Ring Face Seal (ORFS)
• 60 degree Cone (BSPP)
• 60 degree Cone (Metric)

3. Identify the sealing method

Hose fittings mainly vary in size, configuration and thread types. Identifying the sealing method required will help to narrow down your options.

The three most common thread types are:

• O-Ring – The main component in this design is the O-ring seal which creates the seal. The three types of thread are face-seal (flat-face), flange fittings and straight-thread boss fittings.
• Tapered threads – These are available in male and female types. Male tapered threads have fitting threads on the outside, and these are on the inside in female tapered threads.
• Mated angle – These fittings are sealed with straight or parallel threads, and a seal forms when male and female threads connect and the two mating angles join.

4. Detect the fitting design

The next step requires identifying the position of the O-Ring, fitting termination and nose seat. These can be manually measured, but then you will need a seat gauge to get the measurements for your seat angle.

The result of this should be identifying whether your O-Ring is on the inside, outside, in the flange groove or at the nose seat. You should also be able to recognise if the nose seat is flat face, inverted, or standard.

5. Define the thread size

Use a vernier to measure the inside diameter and outside diameter of your thread to give you an accurate thread size result.

 

What next?

Once you’ve determined the hose fitting type, design, sealing method and thread size, you should know exactly which product you need to purchase. However, if you’re still not sure, we recommend getting in touch with a professional.

Flowtechworks with leading manufacturers of hydraulic hose assemblies and components including Eaton Winner, Eaton Aeroquip, Manuli, AlfaGomma, and many more. We can supply a range of components and offer bespoke made-to-order hose assemblies.

For more help with your hydraulic hose fitting product selection or to make an enquiry, please get in touch with us.