DOT push-in tube plug used to cap or seal unused 1/4" OD nylon air-brake tubing during repair, retrofit, or system testing. The Midland 590400 is constructed of brass with a 90-durometer Buna-N (nitrile) O-ring, installs tool-free with a push-to-connect collet, and meets D.O.T. FMVSS 571.106 / SAE J1131 air brake system requirements.Specifications Manufacturer Midland Industries Part Number 590400 Part Type DOT Push-In Tube Plug Tube OD 1/4" Body Material Brass with brass captive eyelet Seal Material Buna-N / Nitrile (90 durometer) Working Pressure Vacuum to 150 PSI Temperature Range -40°F to 200°F Approvals D.O.T. FMVSS 571.106; SAE J1131 ApplicationsThis DOT push-in plug is designed for use in air-brake and pneumatic plumbing on Class 5–8 trucks, tractors, trailers, and heavy equipment, including: Capping unused tee and elbow ports during system reconfiguration Plugging spare ports on air valves, manifolds, and reservoirs Temporary line termination during diagnostic and pressure testing Auxiliary air line plumbing (air horns, air seats, axle locks) For use with DOT-approved 1/4" OD nylon air-brake tubing. Verify tube outside diameter before ordering.
