Understanding Hydraulic Hose Fittings

What are hydraulic hose fittings?

Automotive Lift Repair Florida Hydraulic hose fittings are components used to connect various hydraulic elements (such as pumps, delivery lines, reversing valves, shut-off valves, hydraulic motors, and cylinders) into a closed-loop hydraulic system. These fittings also connect auxiliary components like level gauges, thermometers, and pressure gauges. Essentially, they serve as connectors within a hydraulic circuit.

What are the different types of Automotive Lift Repair Florida hydraulic hose fittings?

1. National Pipe Tapered Fuel (NPTF) Fittings

   – Description: NPTF, or American dry sealed tapered pipe thread, features a 60-degree tapered pipe thread used mainly in North America. It includes two levels of threads, each requiring specific gauge inspections.

   – Usage: Suitable for both external and internal thread end hydraulic hose adapters. However, they should not be interchanged with BSPT pipe fittings due to differences in pitch and thread angle.

2. JIC 37° Flare Fittings

   – Description: Defined by the Society of Automotive Engineers (SAE), these fittings have a 37-degree cone angle used in high-pressure hydraulic pipelines. Both internal and external threads have a flared seat.

   – Usage: Common in high-pressure applications; care must be taken to distinguish between 37° and 45° flare angles.

3. SAE 45° Flare Fittings

   – Description: These fittings feature a 45-degree cone angle and are used mainly with soft copper pipes and in low-pressure applications.

   – Usage: Typically used in refrigerant, fuel lines, and automotive piping. They are similar to JIC fittings but differ in cone angles.

4. O-Ring Face Seal Fittings

   – Description: These fittings use an elastomer O-ring to create a seal when contacting the internal plane of another fitting.

   – Usage: Ideal for applications where leakage prevention is critical.

5. Automotive Lift Repair Florida O-Ring Flange SAE J518

   – Description: This type includes four-bolt split flanges used to connect pumps and motors.

   – Usage: Widely used globally with some variations like the Caterpillar and Poclain flanges.

6. Compression Fittings (Bite Type)

   – Description: These fittings consist of a compression nut, compression ring, and compression seat.

   – Usage: Often used for their ability to create a secure connection with minimal leakage.

What are common mistakes in using hydraulic fittings?

1. Excessive Use of Thread Sealant or PTFE Tape

   – Issue: While sealants might seem like a good idea, they can cause debris that may damage other equipment. For instance, excessive sealant can lead to failures in valves or pressure-reducing components if not properly cleaned.

2. Altering the Original Sealing Structure

   – Issue: Modifying the sealing structure by adding unnecessary materials like PTFE Tape can interfere with proper sealing. For example, covering a gasket with tape can prevent proper contact and sealing.

3. Ignoring Sealing Standards

   – Issue: Simply ensuring no leakage after installation is not sufficient. Proper use of hydraulic adapters and adherence to standard sealing structures is crucial for long-term reliability and safety.

We receive several requests each month for standard fittings. However, in the world of fittings, there is no true “standard” or “typical” option. To get your machine up and running again, you have several fitting types to choose from. This guide aims to help you understand these options better. Here, we’ll focus on how fittings are attached to either a hydraulic hose or a hardline (steel or stainless steel) tube. Knowing the right fitting type before procurement can save you valuable time and money.

 Crimp Fittings

1. Automotive Lift Repair Florida Hydraulic Hose Crimp Fitting:

  If your shop or facility lacks this equipment, you can have a local hydraulic distributor or supplier assemble the hose for you.

2. Automotive Lift Repair Florida Hydraulic Hose Field Attachable Fitting:

   – Description: Field attachable fittings, also known as reusable fittings, do not require a machine for attachment. These fittings can be assembled anywhere as long as the fitting and hose are compatible. Typically, a field attachable fitting consists of two pieces: a socket and a nipple. Assembly instructions vary depending on the specific type of fitting.

The above hydraulic hose fittings are used for high-pressure lines in your machine. For lower pressure lines, such as suction or return lines, barbed fittings are used.

 Barbed Fittings

3. Field Attachable Barbed Fitting:

   – Description: This fitting is a single-piece barbed component that, once inserted into the hose, is secured with a worm clamp or double bolt clamp. It is designed for low-pressure hydraulic applications, such as suction or return lines.

Although JIC and AN fittings appear similar and serve comparable functions, they differ significantly in their applications and specifications. 

 Differences Between AN and JIC Fittings

AN vs. JIC Specifications

Both AN and JIC fittings feature a 37° flare connection on both the male and female ends with straight threads. The seal is achieved by threading the male flared connection into the female coned connection.

– Automotive Lift Repair Florida AN Fittings: AN stands for Air Force-Navy Aeronautical Design Standards. Originating during World War II, these fittings are designed for U.S. military aviation applications and adhere to strict performance and quality standards.

– JIC Fittings: JIC, or Joint Industries Council, fittings are primarily used in industries such as agriculture and are often referred to as SAE J514 Flare fittings. They are governed by the SAE J514 standard and have a lower thread quality compared to AN fittings, making them more cost-effective.

 Key Differences

1. Threads

   – AN 37° Flare Fittings: These fittings have male and female threads made to class 3A/3B UNJ/UNJF standards, featuring a radiused root for improved tensile strength and fatigue resistance. This design is ideal for aerospace and military applications.

   – JIC 37° Flare Fittings: These fittings use male and female threads made to class 2A/2B UN/UNF standards. Class 2A and 2B threads offer a balance of performance, manufacturing efficiency, and cost-effectiveness.

2. Standards

   – AN Fittings: Conform to MIL-F-5509 and AS4841 specifications.

   – SAE/ISO 37° Fittings: Conform to MIL-F-18866 and SAE J514/ISO 8434-2.

What does JIC stand for?

JIC stands for the Joint Industries Council, which established the standards for industrial fittings. These fittings feature a 37° flared seat on both the male and female threaded connections.

What are AN fittings used for?

Automotive Lift Repair Florida AN fittings are predominantly used in U.S. military applications, by military contractors, and in both general and commercial aviation. They are designed to meet high standards specific to these sectors.