3/16 in. x 1/4 in. Composite DOT Male Connector
Overview
The Midland 680303A is a brass D.O.T. male connector that joins 3/16 in. nylon air brake tubing to a 1/4 in. male NPTF port with a single push. Built to FMVSS 571.106 and SAE J1131 for commercial-vehicle air brake service, it seats the tube with one push and holds it against vibration and pressure cycling. The forged brass body resists corrosion in under-chassis environments.
Technical Specifications
| Manufacturer Part # | 680303A |
| Tube Size (Push-In) | 3/16 in. |
| Thread Size | 1/4 in. Male NPTF (1/4 - 18) |
| Connection Type | Push-to-Connect x Male NPTF |
| Pressure Rating | 150 psi |
| Temperature Rating | -40°F to 200°F |
| DOT / SAE | FMVSS 571.106, SAE J1131 |
Materials of Construction
| Body | Brass |
| Collet / Grip Ring | Stainless steel gripper with O-ring seal |
Typical Applications
Used on commercial truck, trailer, and bus air brake systems to connect 3/16 in. DOT air brake tubing to threaded ports on valves, gladhands, and reservoirs. Also serves pneumatic control lines and instrumentation air where a fast, tool-free DOT-rated connection is required.
Cross-Reference and Interchange
This DOT male connector cross-references to these competitor and industry part numbers: 268PPDOT-3B-Y. Replacing one of these? Match nominal size, connections, and rating, or send us your part number and we will confirm the interchange.
Sizing and Installation Resources
- Push-to-Connect Fittings Selection Guide
- NPT Thread Tightening: Turns Past Hand-Tight
- Pipe Size Reference Chart
- Teflon Tape vs. Pipe Dope
Frequently Asked Questions
Is this fitting DOT approved for air brakes?
Yes. It meets FMVSS 571.106 and SAE J1131 for commercial-vehicle air brake systems.
What tubing does it accept?
3/16 in. OD DOT-rated nylon air brake tubing. Cut the tube square and push it fully into the fitting until it bottoms.
Does it need thread sealant?
The NPTF threads are dry-seal, but a thin band of PTFE tape or pipe dope on the male threads is recommended for a leak-free joint.
Can the connection be reused?
Yes. Push the collet in and pull the tube out to release; the fitting can be reconnected.
WARNING: This product can expose you to chemicals including lead, which is known to the State of California to cause cancer and birth defects or other reproductive harm. For more information go to www.P65Warnings.ca.gov.