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Knox Trailers · Hardware & Fasteners
FN309
In stock · ships from Knoxville
This is a straight brass bulkhead fitting, often called a frame nipple, used in air brake systems on heavy trucks and trailers.
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Universal aftermarket part. Always confirm thread type (typically NPT) and length before installation.
Part data verified against 4 catalog sources
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It allows an air line to pass through a frame rail or other bulkhead while maintaining a secure, leak-free connection. The fitting features 3/8 inch male threads on both ends and an overall length of approximately 1.69 inches (1-3/4 inches). Replace this fitting if you notice air leaks at the frame pass-through, corrosion damage, or when upgrading or rerouting air brake lines.
Part Number: FN309
1.69 STRAIGHT BRASS FRAME NIPPLE
Unit: ea
Dealer: Knox Trailers
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