Installation Guides

HOW TO POSITION SAE TUBE FITTINGS

Use this guide to orient the compression end of tube fittings in a specific direction. Simply follow the steps listed below:

Lubricate the o-ring with a lubricant that is compatible with the o-ring material and system fluid.
Back the locknut out.
Finger tighten the tube fitting into the straight thread boss until the metal backup washer makes contact with the face of the boss.
Position the fitting by backing it out until the compression tube fitting end is in the desired direction. Take care to turn the tube fitting no more than one turn while backing out.
Hold the fitting in the desired direction and wrench tighten the locknut until the washer makes contact with the face of the boss.

HOW TO INSTALL COMPRESSION TUBE FITTING CAPS

Use this guide to install tube fitting caps onto pipe ends. Simply follow the steps listed below:

Insert the tube end into the cap to bottom onto the shoulder of the cap.
Finger tighten the nut.
Wrench tighten the nut 1.25 turns while holding the body of the cap with a backup wrench or vise.

Note: Tighten the nut 1/8 of a turn for 1/16, 1/8, and 3/16 inch and 2, 3, and 4 mm fittings.

HOW TO INSTALL COMPRESSION TUBE FITTING PLUGS

Use this guide to install tube fitting plugs. Simply follow the steps listed below:

Remove the nut and ferrule(s) from the tube fitting body.
Finger tighten the plug.
Tighten the plug 1/4 turn beyond the finger-tight position, holding the body with a backup wrench or vise.

Note: Tighten the nut 1/8 of a turn for 1/16, 1/8, and 3/16 inch and 2, 3, and 4 mm fittings.

HOW TO INSTALL COMPRESSION TUBE FITTING INSERTS

Tube fitting inserts are used for soft plastic nylon tubing, including PTFE and PFA tubing. The compression tube fitting insert internally supports the soft tubing and allows the tube to connect to hydraulic ports without collapsing. Use this guide to install tube fitting inserts. Simply follow the steps listed below:

Fully insert the tube into the insert.
Insert both the tube and insert into the port.
Finger tighten the nut.
Wrench tighten the nut 1.25 turns. Be sure to hold the tube fitting body with a backup wrench or vise.

Note: For 3/16 tube fittings, tighten 3/4 turns.

HOW TO INSTALL COMPRESSION TUBE FITTING INSERTS

Fully insert the tube into the insert.
Insert both the tube and insert into the port.
Finger tighten the nut.
Wrench tighten the nut 1.25 turns. Be sure to hold the tube fitting body with a backup wrench or vise.

Note: For 3/16 tube fittings, tighten 3/4 turns.

HOW TO INSTALL O-RING COMPRESSION TUBE FITTING

O-ring tube fittings require a smooth, flat seating surface. The seating surface must be perpendicular to the axis of the threads. Use this guide to install o-ring tube fittings. Simply follow the steps listed below:

Finger tighten the o-ring tube fitting into the port.
The "squeezing" effect on the o-ring can be felt during the last quarter (1/4) turn.
Lightly tighten with a wrench, and the tube fitting is installed.

ASSEMBLING SOCKET WELD TUBE FITTINGS

The type of weld used to join a tube to a socket weld tube fitting is like any other type of tee weld. The root (the point of intersection of the outside of the tube and annular end area of the tube fitting) must be included in the weld zone. The codes applicable to the welding of socket weld tube fittings require that the tube be inserted into the socket until it bottoms against the stop. The tube must then be backed out approximately 1/16 (one sixteenth) of an inch before being welded. If the tube is not backed out, but is welded while against a flat bottom stop, the contraction of the weld fillet and fitting socket can combine to produce a static stress on the weld. During thermal transients, the fitting and the portion of the tube inside the fitting may experience a differential rate of heating or cooling, which can add to the stress level in the weld.

CAN YOU USE TEFLON TAPE OR PIPE DOPE WITH TUBE FITTINGS?

Generally, it is not recommended to use Teflon (PTFE) tape or pipe dope with compression tube fittings. PTFE Tape and pipe dope are meant to be used on hydraulic fittings where the seal is created on the threads. With tube fittings, the seal is created on the ferrule. In some cases, if too much tape is used, the tape can prevent the compression nut from screwing down far enough to create a seal. Stray bits of tape or lumps of pipe dope can also get lodged on the sealing surface of the tube fitting which can cause leaks.

SAFETY PRECAUTIONS WHILE INSTALLING TUBE FITTINGS

Always take care while installing any type of hydraulic fittings, including tube fittings. Follow these steps for a safer installation process.

Do not assemble or tighten tube fittings when the system is pressurized.
Do not bleed the system by loosening the tube fitting nut or tube fitting plug.
Make sure that the tubing rests firmly on the shoulder of the body of the tube fitting before tightening the nut.
Do not use pipe dope or Teflon tape on compression tube fittings.
Do not mix materials or fitting components from multiple manufacturers.
Never turn the tube fitting body. Hold the tube fitting body and turn the nut.
Avoid unnecessary disassembly of unused fittings.

These are not the only safety precautions to take while installing compression tube fittings, always check the manufacturer's recommendations for installation before attempting any installation.

REASSEMBLY OF TUBE FITTINGS

Reassembly of a tube fitting assembly can be an easy and simple process. Simply follow the steps listed below:

Always depressurize the hydraulic system before disassembly of the tube fitting.
Before disassembly, mark the tube at the back of the nut.
Mark a line along the nut and fittings body flats. Use these marks to ensure that you return the nut to the previously pulled-up position.
Insert the tube with preswaged ferrules into the tube fitting until the the front ferrule seats against the tube fitting body.
While holding the body steady, rotate the nut with a wrench to the previously pulled-up position as indicated by the marks on the tube and flats.
You will feel a significant increase in resistance - tighten the nut slightly.