/ Technical Support / By Victory Technical Team (Zhuji Aoke Factory)
Selecting the right pneumatic tubing is critical for safety and efficiency. Whether you are maintaining a semi-truck air brake system or building an automation machine, using the wrong material (like putting PE tubing on a brake line) can lead to catastrophic failure.
As a manufacturer of SAE-compliant tubing, Victory Technology has compiled the most frequently asked questions (FAQ) from our global distributors and fleet mechanics.
🟢 Section 1: Material Selection (Which Tube for What?)
Nylon (PA12): The “Muscle.” Rigid, high-pressure resistant, and chemically stable. It is the industry standard for Truck Air Brakes and fuel lines.
PU (Polyurethane): The “Gymnast.” Extremely flexible and kink-resistant with excellent memory. Best for robotics, automation, and moving machinery.
PE (Polyethylene): The “Economist.” Low cost and chemically inert (food safe). Best for water filtration and low-pressure air, but has poor heat resistance.
For primary braking systems, you must use DOT-approved Nylon Tubing (specifically SAE J844 Type A or B). It withstands the heat of the engine and the high pressure of the braking system without swelling or bursting.
⚠️ Warning: Never use PU or PE tubing for air brake lines. They do not meet DOT safety standards.
Yes. PU is rubber-like and absorbs vibration excellently. However, it lacks the pressure rating of Nylon. Use PU for “push-to-connect” automation circuits inside a cab or control panel, but stick to Nylon for chassis routing.
Absolutely not. PE tubing has a low melting point and low burst pressure. Under the stress of a truck’s operation, it will fail.
🔵 Section 2: Performance & Specs (Pressure & Heat)
Standard SAE J1402 / J844 Nylon Tubing typically handles a working pressure of 150 PSI (1.0 MPa), with a burst pressure rating often exceeding 900 PSI.
Note: Wall thickness and tube diameter (e.g., 3/8″ vs 1/2″) affect the exact rating.
High-quality PA12 Nylon is engineered for extremes: -40°C to +100°C (-40°F to +212°F). This ensures it won’t crack in Canadian winters or melt in Arizona summers.
In normal operating conditions, UV-stabilized Nylon tubing lasts 5–10 years.
Signs to replace: Visible cracks, stiffness (loss of flexibility), or discoloration from UV exposure.
Premature cracking is usually caused by:
UV Exposure: Cheap tubing lacks UV stabilizers.
Chemical Attack: Road salts or battery acid cleaning agents.
Heat Aging: Being routed too close to the exhaust / turbo without heat shielding.
Yes. Straight, Elbow, and Tee push-in fittings work perfectly with Nylon, PU, and PE tubing.
🏭 Factory Pro Tip: Ensure the tube is cut perfectly square (90 degrees). An angled cut will damage the internal O-ring and cause a leak.
Always use a dedicated Tubing Cutter. Do NOT use wire cutters, scissors, or pliers—they crush the tube into an oval shape, preventing the fitting from sealing.
The Tube: Generally, no. Once the metal teeth of a push-in fitting bite into the tube, the surface is scratched. If you pull it out, cut off the scratched 1cm section before re-inserting.
The Fitting: Yes, push-in fittings are reusable.
This depends on the diameter (e.g., 1/4″ tube bends tighter than 1/2″). Never force a tube to bend sharper than its limit, or it will kink and restrict airflow. Use an Elbow Fitting instead.
Not all Nylon is DOT approved. Only tubing marked with “DOT” and the manufacturer’s code (e.g., SAE J844) complies with Federal Motor Vehicle Safety Standards. Victory Technology manufactures fully compliant DOT tubing.
SAE J844 Type B tubing (sizes > 5/16″) is multi-layer. It features a Nylon inner core, a fiber reinforcement braid (mesh), and a protective Nylon outer jacket for extra strength.
While not strictly “required” by law for every inch, color-coding is industry standard for safety:
🔴 Red: Emergency / Supply Line
🔵 Blue: Service / Control Line
⚫ Black: Accessory / Secondary Lines (often UV resistant)
