Sin Ling is a trusted manufacturer of DOT brass fittings and DOT-approved air brake push-in fittings for heavy-duty trucks, trailers, buses, and off-road commercial vehicles. All fittings are fully compliant with FMVSS 571.106 and engineered for seamless installation with SAE J844 Type A & Type B DOT air line fittings, ensuring reliable performance across all regulated air brake systems.

 

Tested to Higher Standards for Real-World Durability

Unlike many DOT push to connect air fittings and commercial one touch fittings commonly found on the market, Sin Ling fittings are verified through third-party laboratory testing, delivering pull-out strength that meets or exceeds the stringent requirements for towing vehicles, axles, trailer applications, and other high-load brake systems.

To maximize durability, every fitting uses a premium HNBR O-ring, offering superior resistance to high temperature, low temperature, ozone, chemical exposure, and long-term compression set—far outperforming standard NBR O-rings used by competitors.

Precision-Machined Brass Components Manufactured In-House

Every critical component — including the brass body, collet teeth, and tube support — is manufactured in-house using multi-spindle CNC machines and rotary transfer machining centers. This ensures exact tolerances, tight sealing geometry, and reliable long-term performance under intense vibration and extreme road conditions.

Complete DOT Push-In Fitting Range

The Sin Ling DOT series includes a full selection of DOT air brake fittings, such as:

• Straight unions
• Male & female connectors
• Reducing connectors
• Elbows (45° / 90°), tees, 
• Bulkhead connectors
• Threaded variations (NPT, NPTF, ORB)

Each fitting is optimized to maintain high flow efficiency, prevent air leakage, and secure long-term sealing performance throughout the brake system lifespan.

Trusted by OEMs, Tier-1 Suppliers, and Aftermarket Distributors Worldwide

With 40+ years of machining expertise, Sin Ling supplies DOT air brake fittings to global commercial vehicle OEMs, Tier-1 manufacturers, pneumatic system integrators, and aftermarket distributors. Our DOT push to connect air fittings and high-performance one touch fittings are engineered for safety, durability, and easy installation, making them the preferred choice for modern heavy-duty pneumatic brake systems.

FAQ

Q1: Are these fittings certified for DOT air brake applications?
Yes. All products comply with FMVSS 571.106 and meet DOT requirements for air brake systems.

Q2: Which tubing types are compatible?
Our fittings are designed for SAE J844 Type A and Type B nylon air brake tubing.

Q3: Do you offer HNBR O-rings for high durability?
Yes. We supply HNBR O-ring and other options for various operating conditions.

Q4: Can Sin Ling support OEM manufacturing or private label programs?
Absolutely. We provide OEM, Tier-1, and aftermarket supply with flexible production capabilities.