{"product_id":"polaris-chain-tensioner-kit-part-39-120","title":"Polaris Chain Tensioner Kit — Part # 39-120","description":"\u003ch2 data-section-id=\"1hyyhue\" data-start=\"38\" data-end=\"82\"\u003eKey Benefits + Pool Cleaner Drive Fitment\u003c\/h2\u003e\n\u003cul data-start=\"84\" data-end=\"716\"\u003e\n\u003cli data-section-id=\"1bdtres\" data-start=\"84\" data-end=\"175\"\u003eGenuine Polaris chain tensioner kit for the Polaris 3900 Sport pressure-side pool cleaner\u003c\/li\u003e\n\u003cli data-section-id=\"ppobmg\" data-start=\"176\" data-end=\"252\"\u003ePart number 39-120 helps customers match the correct replacement component\u003c\/li\u003e\n\u003cli data-section-id=\"nbgzf2\" data-start=\"253\" data-end=\"322\"\u003eHelps maintain proper chain tension inside the cleaner drive system\u003c\/li\u003e\n\u003cli data-section-id=\"jt6gmv\" data-start=\"323\" data-end=\"405\"\u003eSupports smoother cleaner movement when the original tensioner is worn or failed\u003c\/li\u003e\n\u003cli data-section-id=\"17xeet4\" data-start=\"406\" data-end=\"484\"\u003eHelps prevent the cleaner chain from becoming loose, slipping, or misaligned\u003c\/li\u003e\n\u003cli data-section-id=\"10utb2k\" data-start=\"485\" data-end=\"556\"\u003eUseful replacement when servicing the Polaris 3900 Sport drive system\u003c\/li\u003e\n\u003cli data-section-id=\"1ypl4fe\" data-start=\"557\" data-end=\"638\"\u003eOEM-style part designed for proper fit in compatible Polaris cleaner assemblies\u003c\/li\u003e\n\u003cli data-section-id=\"17zvtff\" data-start=\"639\" data-end=\"716\"\u003eHelps restore cleaner performance without replacing the entire pool cleaner\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2 data-section-id=\"kdtf3b\" data-start=\"718\" data-end=\"742\"\u003eQuick Product Summary\u003c\/h2\u003e\n\u003cp data-start=\"744\" data-end=\"1319\"\u003eThe Polaris Chain Tensioner Kit, part number 39-120, is a replacement drive-system component for the Polaris 3900 Sport pressure-side pool cleaner. This kit helps maintain the proper tension on the cleaner’s internal chain so the drive system can operate smoothly and stay aligned. Use this part when your Polaris 3900 Sport has chain slack, drive issues, inconsistent movement, or a worn chain tensioner. Public product references identify Polaris 39-120 as a genuine OEM chain tensioner kit designed for the Polaris 3900 Sport cleaner. \u003cspan class=\"\" data-state=\"closed\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003ch2 data-section-id=\"4megn2\" data-start=\"1321\" data-end=\"1332\"\u003eBest For\u003c\/h2\u003e\n\u003cul data-start=\"1334\" data-end=\"1619\"\u003e\n\u003cli data-section-id=\"146qsv0\" data-start=\"1334\" data-end=\"1382\"\u003ePolaris 3900 Sport pressure-side pool cleaners\u003c\/li\u003e\n\u003cli data-section-id=\"1xy1gn8\" data-start=\"1383\" data-end=\"1427\"\u003eReplacing a worn or failed chain tensioner\u003c\/li\u003e\n\u003cli data-section-id=\"tj2ku9\" data-start=\"1428\" data-end=\"1469\"\u003eRestoring proper internal chain tension\u003c\/li\u003e\n\u003cli data-section-id=\"dgqlh9\" data-start=\"1470\" data-end=\"1500\"\u003eCleaner drive system repairs\u003c\/li\u003e\n\u003cli data-section-id=\"1ymreof\" data-start=\"1501\" data-end=\"1550\"\u003ePool owners matching Polaris part number 39-120\u003c\/li\u003e\n\u003cli data-section-id=\"829chv\" data-start=\"1551\" data-end=\"1619\"\u003eService professionals repairing Polaris 3900 Sport movement issues\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2 data-section-id=\"1u9nex9\" data-start=\"1621\" data-end=\"1640\"\u003eWhy This Matters\u003c\/h2\u003e\n\u003cul data-start=\"1642\" data-end=\"2093\"\u003e\n\u003cli data-section-id=\"15aqtwv\" data-start=\"1642\" data-end=\"1707\"\u003eA loose chain can affect cleaner movement and drive performance\u003c\/li\u003e\n\u003cli data-section-id=\"oa40w6\" data-start=\"1708\" data-end=\"1788\"\u003ePoor chain tension may cause slipping, misalignment, or inconsistent operation\u003c\/li\u003e\n\u003cli data-section-id=\"qxcoje\" data-start=\"1789\" data-end=\"1857\"\u003eReplacing the tensioner can help restore smoother cleaner movement\u003c\/li\u003e\n\u003cli data-section-id=\"ca67tt\" data-start=\"1858\" data-end=\"1930\"\u003eMatching the correct Polaris part number helps avoid wrong-part orders\u003c\/li\u003e\n\u003cli data-section-id=\"1rb4dum\" data-start=\"1931\" data-end=\"2015\"\u003eDrive-system repairs are often more cost-effective than replacing the full cleaner\u003c\/li\u003e\n\u003cli data-section-id=\"1gdjvk8\" data-start=\"2016\" data-end=\"2093\"\u003eA properly tensioned chain helps the Polaris 3900 Sport operate as intended\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2 data-section-id=\"16e1849\" data-start=\"2095\" data-end=\"2140\"\u003eCommon Signs You Need This \/ Use This When\u003c\/h2\u003e\n\u003cul data-start=\"2142\" data-end=\"2639\"\u003e\n\u003cli data-section-id=\"ya9exx\" data-start=\"2142\" data-end=\"2208\"\u003eUse this part when your Polaris 3900 Sport has drive-chain slack\u003c\/li\u003e\n\u003cli data-section-id=\"1cescmw\" data-start=\"2209\" data-end=\"2278\"\u003eUse this replacement when the cleaner movement becomes inconsistent\u003c\/li\u003e\n\u003cli data-section-id=\"1dze9n6\" data-start=\"2279\" data-end=\"2367\"\u003eCommon signs may include slipping, poor wheel drive, stalling, or abnormal drive noise\u003c\/li\u003e\n\u003cli data-section-id=\"20jiww\" data-start=\"2368\" data-end=\"2477\"\u003eReplace the chain tensioner when the original part is worn, damaged, or no longer maintaining chain tension\u003c\/li\u003e\n\u003cli data-section-id=\"wsenrs\" data-start=\"2478\" data-end=\"2550\"\u003eUse this part when your cleaner parts diagram calls for Polaris 39-120\u003c\/li\u003e\n\u003cli data-section-id=\"bl4yu2\" data-start=\"2551\" data-end=\"2639\"\u003eInspect related drive parts if the cleaner still has movement issues after replacement\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003ch2 data-section-id=\"3ipjz4\" data-start=\"2641\" data-end=\"2666\"\u003eProduct Specifications\u003c\/h2\u003e\n\u003cdiv class=\"TyagGW_tableContainer\"\u003e\n\u003cdiv class=\"group TyagGW_tableWrapper flex flex-col-reverse w-fit\" tabindex=\"-1\"\u003e\n\u003ctable data-start=\"2668\" data-end=\"3248\" class=\"w-fit min-w-(--thread-content-width)\"\u003e\n\u003cthead data-start=\"2668\" data-end=\"2695\"\u003e\n\u003ctr data-start=\"2668\" data-end=\"2695\"\u003e\n\u003cth data-start=\"2668\" data-end=\"2684\" data-col-size=\"sm\" class=\"last:pe-10\"\u003eSpecification\u003c\/th\u003e\n\u003cth data-start=\"2684\" data-end=\"2695\" data-col-size=\"md\" class=\"last:pe-10\"\u003eDetails\u003c\/th\u003e\n\u003c\/tr\u003e\n\u003c\/thead\u003e\n\u003ctbody data-start=\"2706\" data-end=\"3248\"\u003e\n\u003ctr data-start=\"2706\" data-end=\"2725\"\u003e\n\u003ctd data-start=\"2706\" data-end=\"2714\" data-col-size=\"sm\"\u003eBrand\u003c\/td\u003e\n\u003ctd data-col-size=\"md\" data-start=\"2714\" data-end=\"2725\"\u003ePolaris\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr data-start=\"2726\" data-end=\"2764\"\u003e\n\u003ctd data-start=\"2726\" data-end=\"2741\" data-col-size=\"sm\"\u003eProduct Name\u003c\/td\u003e\n\u003ctd data-col-size=\"md\" data-start=\"2741\" data-end=\"2764\"\u003eChain Tensioner Kit\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr data-start=\"2765\" data-end=\"2795\"\u003e\n\u003ctd data-start=\"2765\" data-end=\"2785\" data-col-size=\"sm\"\u003ePart Number \/ SKU\u003c\/td\u003e\n\u003ctd data-col-size=\"md\" data-start=\"2785\" data-end=\"2795\"\u003e39-120\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr data-start=\"2796\" data-end=\"2827\"\u003e\n\u003ctd data-start=\"2796\" data-end=\"2812\" data-col-size=\"sm\"\u003eUPC \/ Barcode\u003c\/td\u003e\n\u003ctd data-start=\"2812\" data-end=\"2827\" data-col-size=\"md\"\u003e73891906692\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr data-start=\"2828\" data-end=\"2879\"\u003e\n\u003ctd data-start=\"2828\" data-end=\"2843\" data-col-size=\"sm\"\u003eProduct Type\u003c\/td\u003e\n\u003ctd data-col-size=\"md\" data-start=\"2843\" data-end=\"2879\"\u003ePool cleaner chain tensioner kit\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr data-start=\"2880\" data-end=\"2925\"\u003e\n\u003ctd data-start=\"2880\" data-end=\"2895\" data-col-size=\"sm\"\u003eCleaner Type\u003c\/td\u003e\n\u003ctd data-col-size=\"md\" data-start=\"2895\" data-end=\"2925\"\u003ePressure-side pool cleaner\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr data-start=\"2926\" data-end=\"2975\"\u003e\n\u003ctd data-start=\"2926\" data-end=\"2953\" data-col-size=\"sm\"\u003eCompatible Cleaner Model\u003c\/td\u003e\n\u003ctd data-col-size=\"md\" data-start=\"2953\" data-end=\"2975\"\u003ePolaris 3900 Sport\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr data-start=\"2976\" data-end=\"3028\"\u003e\n\u003ctd data-start=\"2976\" data-end=\"2990\" data-col-size=\"sm\"\u003eApplication\u003c\/td\u003e\n\u003ctd data-col-size=\"md\" data-start=\"2990\" data-end=\"3028\"\u003eCleaner drive system chain tension\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr data-start=\"3029\" data-end=\"3117\"\u003e\n\u003ctd data-start=\"3029\" data-end=\"3035\" data-col-size=\"sm\"\u003eUse\u003c\/td\u003e\n\u003ctd data-col-size=\"md\" data-start=\"3035\" data-end=\"3117\"\u003eReplacement tensioner kit for maintaining internal chain alignment and tension\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr data-start=\"3118\" data-end=\"3181\"\u003e\n\u003ctd data-start=\"3118\" data-end=\"3141\" data-col-size=\"sm\"\u003eOEM \/ Genuine Status\u003c\/td\u003e\n\u003ctd data-col-size=\"md\" data-start=\"3141\" data-end=\"3181\"\u003eGenuine Polaris OEM replacement part\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003ctr data-start=\"3182\" data-end=\"3248\"\u003e\n\u003ctd data-start=\"3182\" data-end=\"3193\" data-col-size=\"sm\"\u003eCategory\u003c\/td\u003e\n\u003ctd data-col-size=\"md\" data-start=\"3193\" data-end=\"3248\"\u003ePool Cleaners \u0026amp; Chemicals in Pool \u0026amp; Spa Accessories\u003c\/td\u003e\n\u003c\/tr\u003e\n\u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003ch2 data-section-id=\"1hf0woe\" data-start=\"3250\" data-end=\"3282\"\u003eCompatibility \/ Fitment Notes\u003c\/h2\u003e\n\u003cp data-start=\"3284\" data-end=\"3624\"\u003eThe Polaris 39-120 Chain Tensioner Kit is designed for the Polaris 3900 Sport pressure-side pool cleaner. Multiple public parts listings identify 39-120 as the chain tensioner kit for the Polaris 3900 Sport, and PoolZoom lists it as a Polaris Genuine OEM 3900 Chain Tensioner Kit with UPC 738919066922. \u003cspan class=\"\" data-state=\"closed\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp data-start=\"3626\" data-end=\"3964\"\u003eDo not assume this part fits other Polaris cleaner models such as the Polaris 180, 280, 360, 380, 3900 Sport alternatives, Quattro, or robotic cleaners unless your parts diagram specifically calls for part number 39-120. Before ordering, confirm your cleaner model and compare the part number against the cleaner’s exploded parts diagram.\u003c\/p\u003e\n\u003ch2 data-section-id=\"3ww6d2\" data-start=\"3966\" data-end=\"3993\"\u003eInstallation \/ Use Notes\u003c\/h2\u003e\n\u003cp data-start=\"3995\" data-end=\"4298\"\u003eTurn off the booster pump and pool equipment before removing the cleaner from the pool for service. Open the cleaner according to the Polaris 3900 Sport service instructions and inspect the chain, drive components, chain guard, wheels, bearings, and related internal parts while replacing the tensioner.\u003c\/p\u003e\n\u003cp data-start=\"4300\" data-end=\"4584\"\u003eIf the chain tensioner is worn, other drive components may also show wear. If the cleaner still slips, stalls, or moves inconsistently after replacement, inspect the chain, drive shaft, wheels, bearings, belts or gears, water management system, backup valve, feed hose, and wheel RPM.\u003c\/p\u003e\n\u003ch2 data-section-id=\"1bnh3vx\" data-start=\"4586\" data-end=\"4608\"\u003eBuy with Confidence\u003c\/h2\u003e\n\u003cp data-start=\"4610\" data-end=\"5026\"\u003eBenchmark Pool Supply helps pool owners and service professionals choose the correct Polaris cleaner parts by part number, cleaner model, and real-world repair use. Small drive-system parts can be easy to confuse, so matching Polaris 39-120 to the Polaris 3900 Sport is important before ordering. Our goal is to help customers avoid wrong-part purchases and keep their pressure-side pool cleaners operating properly.\u003c\/p\u003e","brand":"Polaris","offers":[{"title":"Default Title","offer_id":43512925913162,"sku":"39-120","price":44.95,"currency_code":"USD","in_stock":false}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0637\/6580\/7178\/files\/81gAfytBSDL._AC_SX679.jpg?v=1776122838","url":"https:\/\/benchmarkpoolsupply.com\/products\/polaris-chain-tensioner-kit-part-39-120","provider":"Benchmark Pool Supply","version":"1.0","type":"link"}