Tube Nuts & Sleeves

Tube nuts and sleeves are used in hydraulic systems to secure a tube into a fitting and create a strong, leak-free connection.

The sleeve (ferrule) bites into the outside of the tube when tightened, gripping it firmly and forming the seal.
The tube nut then provides the clamping force, locking the sleeve and tube into the fitting body.

They are typically used in:

• Hydraulic lines for high-pressure applications.
• Industrial machinery and mobile equipment.
• Compression fitting systems such as DIN 2353 and JIC.

Tube nuts and sleeves work together to hold hydraulic tubes securely in place, prevent leaks, and withstand high system pressures.

Cut the tube:

• Use a proper tube cutter or saw to cut the tube square (90°).
• Avoid angled cuts, which can cause poor sealing.

Deburr the ends:

• Remove burrs inside and outside the tube with a deburring tool.
• This prevents damage to the sleeve and ensures a smooth seal.

Slide on the nut and sleeve:

• First slide the tube nut onto the tube, thread side facing the fitting.
• Then slide the sleeve on behind it.

Insert the tube into the fitting body:

• Push the tube firmly into the fitting body until it bottoms out.
• The sleeve should be positioned between the nut and the fitting body.

Hand tighten the nut:

• Screw the nut onto the fitting by hand until it stops.
• This keeps everything aligned.

Tighten with a spanner:

• Use a wrench/spanner to tighten the nut further.
• Follow manufacturer torque specs if available (typically 1 1/4 to 1 1/2 turns past hand-tight for DIN compression).
• As you tighten, the sleeve bites into the tube, creating a secure, leak-free grip.

Check the assembly:

• Make sure the tube cannot pull out.
• Re-pressurise the system gradually and inspect for leaks.