1/4 in. x 1/8 in. Push-In x Male NPT DOT Adapter, Composite
1/4 in. x 1/8 in. Push-In x Male NPT DOT Adapter, Composite
Sizes in This Series
Composite DOT push-in to male NPT straight adapters. Jump to another size or add it straight to your cart:
| Size | Part # | Price | Cart |
| 1/4 in. x 1/8 in. (this page) | 680402C | $3.80 | — |
| 3/8 in. x 1/2 in. | 680608C | $10.99 | Add to cart |
Overview
The Midland 680402C is a composite-body D.O.T. adapter connecting 1/4 in. push-in air brake tubing to a 1/8 in. male NPT port. Its glass-reinforced composite body is UV- and vibration-resistant and noticeably lighter than brass, cutting weight on long trailer runs while meeting D.O.T. and SAE air brake requirements. One-touch insertion speeds installation.
Technical Specifications
| Manufacturer Part # | 680402C |
| Tube Size (Push-In) | 1/4 in. |
| Thread Size | 1/8 in. Male NPT (1/8 - 27) |
| Connection Type | Push-to-Connect x Male NPT |
| Pressure Rating | 145 psi |
| Temperature Rating | -40°F to 140°F |
| DOT / SAE | FMVSS 571.106, SAE J1131 |
Materials of Construction
| Body | Glass-reinforced composite |
| Collet / Grip Ring | Stainless steel gripper with O-ring seal |
Typical Applications
Used where a lighter, corrosion-proof alternative to brass is preferred on truck and trailer air brake lines, connecting 1/4 in. DOT tubing to 1/8 in. NPT ports on valves and reservoirs. Well suited to under-chassis runs exposed to road salt and weathering.
Cross-Reference and Interchange
This composite DOT adapter cross-references to these competitor and industry part numbers: 268PPCDOT-4A, CDOT1468-4-2, KV2H07-34S, QL1368-4A, S768PMT-4-2. 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 the composite body as strong as brass?
For air brake service it meets the same FMVSS 571.106 and SAE J1131 standards, rated to 145 psi with added UV and corrosion resistance.
What tubing does it accept?
1/4 in. OD DOT-rated nylon air brake tubing. Cut square and push fully in until it bottoms.
Does it need thread sealant?
A thin band of PTFE tape or pipe dope on the male NPT threads is recommended for a leak-free seal.
What is the temperature limit?
-40°F to 140°F, lower than the brass version, so keep it away from high-heat zones.
WARNING: This product can expose you to chemicals 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.