Description BLUE GLADHAND SEAL – SOLD AS INDIVIDUAL SEALS Part Number: FS18581C Direct replacement (cross ref) for DA9017B. Product Overview This blue gladhand seal is used in the service line of the air brake system. It creates the seal between tractor and trailer air connections and keeps air pressure where it belongs. This unit is typically used for the blue (service) side gladhand. What the Part Does The seal sits inside the gladhand and forms the contact point when the tractor and trailer lines are connected. Its job is simple — keep air from leaking out at the connection. Even though it’s a small part, it plays a big role. Without a good seal, the system cannot hold pressure properly, and that affects how the brakes respond. Common Problems This Part Solves Worn gladhand seals show up fast. You’ll hear a hissing sound at the connection, see slower air pressure buildup, or get low air warnings after hooking up a trailer. Over time, the rubber seal can harden, crack, or flatten from repeated use, weather exposure, and dirt. When that happens, it no longer seals tight, and air loss becomes constant. Why Replacement Matters A leaking seal might not seem like a big deal at first, but it adds up. The compressor has to work harder, air pressure takes longer to build, and brake response can suffer if pressure drops too much. The good news is that this is one of the easiest and cheapest fixes you can make. Replacing the seal early keeps the system working properly and avoids bigger air system issues. Compatibility and Fitment This seal replaces OEM part DA9017B and is used in standard blue service line gladhands. Always confirm the application, but most standard setups use this style seal. Black gladhand seal usually have different uses, so be careful. Installation and Service Notes Installation is quick. Remove the old seal from the gladhand and press the new one into place evenly. No special tools are needed, but make sure it sits flat and fully seated. Use Case Commonly used in routine air system maintenance, pre-trip fixes, or anytime there’s a leak at the trailer connection. Many drivers keep extras on hand because they’re easy to swap and save time on the road. About Us We’re a family-owned group of Peterbilt dealerships dedicated to getting you the parts you need quickly and affordably. Whether you’re looking for Paccar OEM parts, reliable aftermarket replacements, or popular upgrades like seats and filters, we make it easy to keep your truck running and on the road. If you don’t see what you need online, just give us a call or send an email — chances are we can get it. We pride ourselves on fast service, fair prices, and being a partner you can depend on when downtime isn’t an option FAQs Q1: Are blue seals different from red ones? A: Yes. Blue is typically used for the service line, while red is for the emergency line. The seals can look similar, but they’re installed based on the gladhand they’re going into. How often should gladhand seals be replaced? A: There’s no exact schedule, but they’re often replaced during routine inspections or whenever a leak shows up. Can I replace it on the road? A: Yes, this is one of the easiest roadside fixes. You can usually swap it out by hand in a couple of minutes and get back on the road. Should I replace both seals at the same time? A: It’s a smart move. If one is worn, the other is likely in similar condition. What if it still leaks after replacing the seal? A: If the leak continues, check the gladhand face for damage or wear. A rough or uneven surface won’t seal properly, even with a new gasket.
