{"product_id":"n20879dg-genuine-haldex®-automatic-drain-valve","title":"N20879DG | Genuine Haldex® Automatic Drain Valve","description":"\u003cp\u003e\u003cstrong\u003eDescription:\u003c\/strong\u003e Automatic Drain Valve\u003cbr\u003e\u003cstrong\u003eCondition:\u003c\/strong\u003e New\u003cbr\u003e\u003cstrong\u003eBrand:\u003c\/strong\u003e Haldex®\u003cbr\u003e\u003cstrong\u003ePart Number:\u003c\/strong\u003e N20879DG\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eVehicle Fitment\u003c\/strong\u003e\u003c\/p\u003e\n\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e \n\u003cp data-path-to-node=\"3\"\u003e\u003cb data-path-to-node=\"3\" data-index-in-node=\"0\"\u003e1. Universal Commercial Vehicle Compatibility\u003c\/b\u003e\u003c\/p\u003e\n\u003cp data-path-to-node=\"4\"\u003eBecause heavy-duty pneumatic air brake networks rely on standardized reservoir port sizes, this Haldex automatic drain valve features a universal \u003cb data-path-to-node=\"4\" data-index-in-node=\"146\"\u003e1\/2\" NPT (National Pipe Thread)\u003c\/b\u003e male mounting port. This allows it to serve as a direct-fit or upgrade replacement across practically all major heavy-duty truck, bus, and trailer platforms, including:\u003c\/p\u003e\n\u003cul data-path-to-node=\"5\"\u003e\n\u003cli\u003e\n\u003cp data-path-to-node=\"5,0,0\"\u003e\u003cb data-path-to-node=\"5,0,0\" data-index-in-node=\"0\"\u003eSemi-Trucks:\u003c\/b\u003e Freightliner, Kenworth, Peterbilt, International (Navistar), Volvo, Mack, and Western Star.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp data-path-to-node=\"5,1,0\"\u003e\u003cb data-path-to-node=\"5,1,0\" data-index-in-node=\"0\"\u003eCommercial Buses \u0026amp; Coaches:\u003c\/b\u003e MCI, Prevost, Gillig, and Blue Bird transit\/school buses.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp data-path-to-node=\"5,2,0\"\u003e\u003cb data-path-to-node=\"5,2,0\" data-index-in-node=\"0\"\u003eHeavy Duty Trailers:\u003c\/b\u003e Vocational trailers equipped with standalone air brake distribution systems (Great Dane, Utility, Wabash).\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp data-path-to-node=\"6\"\u003e\u003cb data-path-to-node=\"6\" data-index-in-node=\"0\"\u003e2. System Integration\u003c\/b\u003e\u003c\/p\u003e\n\u003cp data-path-to-node=\"7\"\u003eThis valve is installed directly into the lowest port of the vehicle's primary (wet) or secondary (dry) air storage tanks. It utilizes the vehicle's brake application pressure drops (or an auxiliary governor signal line depending on the specific plumbing configuration) to automatically cycle open and \"spit\" condensed water and compressor oil mist out of the air system before it can travel downstream to corrupt ABS modulators, brake chambers, or leveling valves.\u003c\/p\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003eThe Automatic Drain Valve is a premium, mechanical pneumatic safety valve engineered to protect commercial vehicle air systems from the destructive effects of moisture and oil contamination.\u003c\/p\u003e\n\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e \n\u003cp data-path-to-node=\"3\"\u003e\u003cb data-path-to-node=\"3\" data-index-in-node=\"0\"\u003e1. What is it?\u003c\/b\u003e\u003c\/p\u003e\n\u003cp data-path-to-node=\"4\"\u003eCommonly known in the heavy-duty trucking industry as a \u003cb data-path-to-node=\"4\" data-index-in-node=\"56\"\u003e\"spitter valve\"\u003c\/b\u003e or \u003cb data-path-to-node=\"4\" data-index-in-node=\"75\"\u003emoisture ejector\u003c\/b\u003e, this device is installed at the lowest point of an air brake reservoir tank. It serves as an automated alternative to manual pull-cord drain valves, eliminating the need for drivers or fleet mechanics to manually drain water from air tanks every day.\u003c\/p\u003e\n\u003cp data-path-to-node=\"5\"\u003e\u003cb data-path-to-node=\"5\" data-index-in-node=\"0\"\u003e2. Core Functions\u003c\/b\u003e\u003c\/p\u003e\n\u003cul data-path-to-node=\"6\"\u003e\n\u003cli\u003e\n\u003cp data-path-to-node=\"6,0,0\"\u003e\u003cb data-path-to-node=\"6,0,0\" data-index-in-node=\"0\"\u003eAutomated Moisture \u0026amp; Contaminant Purging:\u003c\/b\u003e As compressed air cools inside the vehicle's steel or aluminum storage tanks, water vapor condenses into liquid water, and compressor oil mist settles at the bottom. This valve automatically senses pressure drops (such as when the brakes are applied or when the compressor cycles) and momentarily opens to forcefully eject (\"spit\") these contaminants out of the system.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp data-path-to-node=\"6,1,0\"\u003e\u003cb data-path-to-node=\"6,1,0\" data-index-in-node=\"0\"\u003eCorrosion \u0026amp; Component Protection:\u003c\/b\u003e By constantly removing water and oil, it prevents liquid from traveling downstream into the brake lines. This protects expensive pneumatic components—such as ABS modulator valves, air dryers, leveling valves, and brake chambers—from internal rust, seal degradation, and winter freeze-ups.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003cli\u003e\n\u003cp data-path-to-node=\"6,2,0\"\u003e\u003cb data-path-to-node=\"6,2,0\" data-index-in-node=\"0\"\u003eIntegrated Maintenance Features:\u003c\/b\u003e The N20879DG model features a standard 1\/2\" NPT inlet mounting thread and includes an internal fine-mesh screen or filter to prevent carbon flakes and debris from jamming the main sealing seat open, ensuring leak-free operation.\u003c\/p\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eSigns of Faulty\u003c\/strong\u003e\u003c\/p\u003e\n\u003ctable width=\"100%\"\u003e\n\u003ctbody\u003e\n\u003ctr\u003e\n\u003ctd\u003e \n\u003cp data-path-to-node=\"3\"\u003e\u003cstrong\u003e1. Constant Air Leaking \/ Continuous Hissing (\"Stuck Open\")\u003c\/strong\u003e\u003c\/p\u003e\n\u003cp data-path-to-node=\"4\"\u003eThe most common sign of failure is a continuous hiss of escaping air from the bottom of the valve when the air tanks are fully charged. This happens when carbon flakes from the air compressor, rust scales, or debris bypass the internal screen and get trapped between the rubber seal and the valve seat, preventing it from closing completely. This creates a parasitic air leak that forces your compressor to work twice as hard.\u003c\/p\u003e\n\u003cp data-path-to-node=\"5\"\u003e\u003cb data-path-to-node=\"5\" data-index-in-node=\"0\"\u003e2. Excessive Water in the Air Tanks During Manual Checks\u003c\/b\u003e\u003c\/p\u003e\n\u003cp data-path-to-node=\"6\"\u003eIf you open the manual petcock or pull-cord drain valve on your auxiliary tanks and a large stream of water or oily sludge pours out, the Haldex automatic valve has stopped cycling. When internal springs weaken or the internal pressure-sensing piston gets gummed up with thick oil sludge, it stops opening (\"spitting\"), allowing moisture to dangerously build up inside the reservoir.\u003c\/p\u003e\n\u003cp data-path-to-node=\"7\"\u003e\u003cb data-path-to-node=\"7\" data-index-in-node=\"0\"\u003e3. Frequent, Erratic, or Loud \"Spitting\"\u003c\/b\u003e\u003c\/p\u003e\n\u003cp data-path-to-node=\"8\"\u003eWhile a healthy valve should make a short, sharp \"psst\" sound when air pressures fluctuate, a faulty unit might begin to cycle rapidly and loudly every few seconds, or it might get stuck in an endless clicking loop. This erratic behavior indicates that the internal diaphragm is ruptured or the control line supplying the pressure signal is blocked or leaking.\u003c\/p\u003e\n\u003cp data-path-to-node=\"9\"\u003e\u003cb data-path-to-node=\"9\" data-index-in-node=\"0\"\u003e4. White or Yellow Sludge Built Up Around the Discharge Port\u003c\/b\u003e\u003c\/p\u003e\n\u003cp data-path-to-node=\"10\"\u003eIf you look beneath the truck at the valve's exhaust port and see a heavy, crusty accumulation of thick white aluminum corrosion or milky-yellow oil emulsion, the valve is heavily contaminated. This sludge eventually glues the internal mechanical parts together, causing total component seizure.\u003c\/p\u003e\n\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e \u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eManufacturer Information:\u003cbr\u003e\u003c\/strong\u003e\u003cstrong\u003eHaldex\u003c\/strong\u003e® is a Sweden-based manufacturer specializing in brake and air suspension systems for heavy duty vehicles. Its product line consists of brake components for wheel ends, including disc brakes, brake adjusters, and actuators. It also offers air control products such as compressed air dryers, valves, ABS, and EBS. All these Haldex products are designed with safety and efficient operation in mind, cutting down on potential hazards and maintenance costs in the long run. Today, Haldex runs manufacturing and R\u0026amp;D facilities in 19 countries across four continents. It is dedicated to producing high-quality brake and suspension parts for its customers all around the world as well as developing new technologies for the future.\u003c\/p\u003e\n\u003cp\u003eWarranty\u003cbr\u003eFirst Truck Parts offers a \u003cstrong\u003e365-days warranty\u003c\/strong\u003e for all types of parts and in any condition. The warranty applies only to buyers who have placed an order on our website.\u003c\/p\u003e","brand":"Haldex®","offers":[{"title":"Default Title","offer_id":48847306916084,"sku":"N20879DG","price":389.0,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0605\/1479\/5764\/files\/s-l1600_86cd1e5c-a420-456a-9093-80126768bb65.webp?v=1783792992","url":"https:\/\/firsttruckparts.com\/products\/n20879dg-genuine-haldex%c2%ae-automatic-drain-valve","provider":"First Truck Parts","version":"1.0","type":"link"}