{"product_id":"porter-cable-904689-head-valve-seal-genuine-oem-replacement-pneumatic-nailer-head-valve-seal","title":"Porter-Cable 904689 Head Valve Seal – Genuine OEM Replacement Pneumatic Nailer Head Valve Seal","description":"\u003cdiv class=\"\" data-turn-id-container=\"417fcf50-e87c-4501-ab78-cbba68f0bd89\" data-is-intersecting=\"true\"\u003e\n\u003csection class=\"text-token-text-primary w-full focus:outline-none has-data-writing-block:pointer-events-none [\u0026amp;:has([data-writing-block])\u0026gt;*]:pointer-events-auto R6Vx5W_threadScrollVars scroll-mb-[calc(var(--scroll-root-safe-area-inset-bottom,0px)+var(--thread-response-height))] scroll-mt-(--sticky-padding-top)\" dir=\"auto\" data-turn-id=\"417fcf50-e87c-4501-ab78-cbba68f0bd89\" data-turn-id-container=\"417fcf50-e87c-4501-ab78-cbba68f0bd89\" data-testid=\"conversation-turn-547\" data-turn=\"user\"\u003e\u003c\/section\u003e\n\u003cbr\u003e\n\u003c\/div\u003e\n\u003cdiv class=\"\" data-turn-id-container=\"request-6a564ce8-dd20-83ea-a458-fe6abd848766-96\" data-is-intersecting=\"true\"\u003e\n\u003csection class=\"text-token-text-primary w-full focus:outline-none has-data-writing-block:pointer-events-none [\u0026amp;:has([data-writing-block])\u0026gt;*]:pointer-events-auto R6Vx5W_threadScrollVars scroll-mb-[calc(var(--scroll-root-safe-area-inset-bottom,0px)+var(--thread-response-height))] scroll-mt-[calc(var(--header-height)+min(200px,max(70px,20svh)))]\" dir=\"auto\" data-turn-id=\"request-6a564ce8-dd20-83ea-a458-fe6abd848766-96\" data-turn-id-container=\"request-6a564ce8-dd20-83ea-a458-fe6abd848766-96\" data-testid=\"conversation-turn-548\" data-turn=\"assistant\"\u003e\n\u003cdiv class=\"text-base my-auto mx-auto pb-15 [--thread-content-margin:var(--thread-content-margin-xs,calc(var(--spacing)*4))] @w-sm\/main:[--thread-content-margin:var(--thread-content-margin-sm,calc(var(--spacing)*6))] @w-lg\/main:[--thread-content-margin:var(--thread-content-margin-lg,calc(var(--spacing)*16))] px-(--thread-content-margin)\"\u003e\n\u003cdiv data-conversation-screenshot-content=\"\" class=\"[--thread-content-max-width:40rem] @w-lg\/main:[--thread-content-max-width:48rem] mx-auto max-w-(--thread-content-max-width) flex-1 group\/turn-messages focus-visible:outline-hidden relative flex w-full min-w-0 flex-col agent-turn\"\u003e\n\u003cdiv class=\"flex max-w-full flex-col gap-4 grow\"\u003e\n\u003cdiv data-message-author-role=\"assistant\" data-message-id=\"b523525d-d5ff-4acb-a19d-fc79e5a38691\" data-turn-start-message=\"true\" dir=\"auto\" data-message-model-slug=\"gpt-5-5\" class=\"min-h-8 text-message relative flex w-full flex-col items-end gap-2 text-start break-words whitespace-normal outline-none keyboard-focused:focus-ring [.text-message+\u0026amp;]:mt-1\" tabindex=\"0\"\u003e\n\u003cdiv class=\"flex w-full flex-col gap-1 empty:hidden\"\u003e\n\u003cdiv class=\"streaming-animation markdown prose dark:prose-invert wrap-break-word w-full light markdown-new-styling\"\u003e\n\u003cp data-start=\"0\" data-end=\"212\"\u003e\u003cstrong data-start=\"0\" data-end=\"16\"\u003ePart Number:\u003c\/strong\u003e 904689\u003cbr data-start=\"23\" data-end=\"26\"\u003e\u003cstrong data-start=\"26\" data-end=\"39\"\u003eCategory:\u003c\/strong\u003e Pneumatic Nailer Parts → Head Valve Components → Head Valve Seals\u003cbr data-start=\"105\" data-end=\"108\"\u003e\u003cstrong data-start=\"108\" data-end=\"117\"\u003eType:\u003c\/strong\u003e Porter-Cable 904689 Head Valve Seal – Genuine OEM Replacement Pneumatic Nailer Head Valve Seal\u003c\/p\u003e\n\u003chr data-start=\"214\" data-end=\"217\"\u003e\n\u003cp data-start=\"317\" data-end=\"1004\"\u003eThe \u003cstrong data-start=\"321\" data-end=\"360\"\u003ePorter-Cable 904689 Head Valve Seal\u003c\/strong\u003e is a genuine OEM replacement seal designed for compatible \u003cstrong data-start=\"419\" data-end=\"460\"\u003ePorter-Cable pneumatic finish nailers\u003c\/strong\u003e. Installed at the top of the cylinder beneath the head cap, this seal creates an airtight barrier for the head valve, allowing the nailer to cycle properly and maintain consistent air pressure. Manufactured to original equipment specifications, it provides a direct-fit replacement for worn, damaged, or leaking seals, helping restore reliable firing performance and reduce air leaks. Because head valve seals compress during installation, they should be replaced whenever removed to ensure a proper seal.\u003cspan class=\"\" data-state=\"closed\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003chr data-start=\"1175\" data-end=\"1178\"\u003e\n\u003ch2 data-section-id=\"939trr\" data-start=\"1180\" data-end=\"1206\"\u003eKey Features \u0026amp; Benefits\u003c\/h2\u003e\n\u003cul data-start=\"1208\" data-end=\"1638\"\u003e\n\u003cli data-section-id=\"h5ckb0\" data-start=\"1208\" data-end=\"1233\"\u003e\n\u003cstrong data-start=\"1210\" data-end=\"1226\"\u003ePart Number:\u003c\/strong\u003e 904689\u003c\/li\u003e\n\u003cli data-section-id=\"vjgkmv\" data-start=\"1234\" data-end=\"1277\"\u003eGenuine OEM Porter-Cable replacement part\u003c\/li\u003e\n\u003cli data-section-id=\"msowjm\" data-start=\"1278\" data-end=\"1340\"\u003eReplacement head valve seal for compatible pneumatic nailers\u003c\/li\u003e\n\u003cli data-section-id=\"wlbgy5\" data-start=\"1341\" data-end=\"1403\"\u003eCreates an airtight seal between the head valve and cylinder\u003c\/li\u003e\n\u003cli data-section-id=\"cmt9bq\" data-start=\"1404\" data-end=\"1456\"\u003eHelps eliminate air leaks from the top of the tool\u003c\/li\u003e\n\u003cli data-section-id=\"jmsbws\" data-start=\"1457\" data-end=\"1519\"\u003eDurable sealing material designed for pneumatic applications\u003c\/li\u003e\n\u003cli data-section-id=\"p6iksq\" data-start=\"1520\" data-end=\"1548\"\u003eDirect-fit OEM replacement\u003c\/li\u003e\n\u003cli data-section-id=\"vgnwhe\" data-start=\"1549\" data-end=\"1638\"\u003eManufactured to original equipment specifications \u003cspan class=\"\" data-state=\"closed\"\u003e\u003c\/span\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003chr data-start=\"1640\" data-end=\"1643\"\u003e\n\u003ch2 data-section-id=\"1cgu054\" data-start=\"1645\" data-end=\"1672\"\u003eTechnical Specifications\u003c\/h2\u003e\n\u003cp data-start=\"1674\" data-end=\"1697\"\u003e\u003cstrong data-start=\"1674\" data-end=\"1690\"\u003ePart Number:\u003c\/strong\u003e 904689\u003c\/p\u003e\n\u003cp data-start=\"1699\" data-end=\"1754\"\u003e\u003cstrong data-start=\"1699\" data-end=\"1716\"\u003eManufacturer:\u003c\/strong\u003e Porter-Cable \/ Stanley Black \u0026amp; Decker\u003c\/p\u003e\n\u003cp data-start=\"1756\" data-end=\"1789\"\u003e\u003cstrong data-start=\"1756\" data-end=\"1773\"\u003eProduct Type:\u003c\/strong\u003e Head Valve Seal\u003c\/p\u003e\n\u003cp data-start=\"1791\" data-end=\"1837\"\u003e\u003cstrong data-start=\"1791\" data-end=\"1804\"\u003eMaterial:\u003c\/strong\u003e Pneumatic-grade sealing material\u003c\/p\u003e\n\u003cp data-start=\"1839\" data-end=\"1890\"\u003e\u003cstrong data-start=\"1839\" data-end=\"1855\"\u003eApplication:\u003c\/strong\u003e Pneumatic Finish Nailer Head Valve\u003c\/p\u003e\n\u003cp data-start=\"1892\" data-end=\"1909\"\u003e\u003cstrong data-start=\"1892\" data-end=\"1905\"\u003eOEM Part:\u003c\/strong\u003e Yes\u003c\/p\u003e\n\u003cp data-start=\"1911\" data-end=\"1980\"\u003e\u003cstrong data-start=\"1911\" data-end=\"1924\"\u003eQuantity:\u003c\/strong\u003e Sold Individually \u003cspan class=\"\" data-state=\"closed\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003chr data-start=\"1982\" data-end=\"1985\"\u003e\n\u003ch2 data-section-id=\"17z2fqi\" data-start=\"1987\" data-end=\"2013\"\u003eCompatible Applications\u003c\/h2\u003e\n\u003cp data-start=\"2015\" data-end=\"2114\"\u003eThe \u003cstrong data-start=\"2019\" data-end=\"2058\"\u003ePorter-Cable 904689 Head Valve Seal\u003c\/strong\u003e fits compatible Porter-Cable finish nailers, including:\u003c\/p\u003e\n\u003ch3 data-section-id=\"1u59pd8\" data-start=\"2116\" data-end=\"2132\"\u003ePorter-Cable\u003c\/h3\u003e\n\u003cul data-start=\"2134\" data-end=\"2172\"\u003e\n\u003cli data-section-id=\"qbfs8s\" data-start=\"2134\" data-end=\"2153\"\u003e\u003cstrong data-start=\"2136\" data-end=\"2153\"\u003eFN250B Type 1\u003c\/strong\u003e\u003c\/li\u003e\n\u003cli data-section-id=\"7uwdfj\" data-start=\"2154\" data-end=\"2172\"\u003e\u003cstrong data-start=\"2156\" data-end=\"2172\"\u003eFN251 Type 1\u003c\/strong\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp data-start=\"2174\" data-end=\"2330\"\u003eAlways verify your nailer model, type number, and original part number before ordering to ensure proper compatibility. \u003cspan class=\"\" data-state=\"closed\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003chr data-start=\"2332\" data-end=\"2335\"\u003e\n\u003ch2 data-section-id=\"isg4mk\" data-start=\"2337\" data-end=\"2371\"\u003eFunction of the Head Valve Seal\u003c\/h2\u003e\n\u003cp data-start=\"2373\" data-end=\"2419\"\u003eThe \u003cstrong data-start=\"2377\" data-end=\"2403\"\u003e904689 Head Valve Seal\u003c\/strong\u003e is designed to:\u003c\/p\u003e\n\u003cul data-start=\"2421\" data-end=\"2720\"\u003e\n\u003cli data-section-id=\"1dcskcm\" data-start=\"2421\" data-end=\"2465\"\u003eCreate an airtight seal for the head valve\u003c\/li\u003e\n\u003cli data-section-id=\"1tqfam2\" data-start=\"2466\" data-end=\"2510\"\u003eMaintain proper air pressure during firing\u003c\/li\u003e\n\u003cli data-section-id=\"1yae5m2\" data-start=\"2511\" data-end=\"2549\"\u003ePrevent air leakage from the top cap\u003c\/li\u003e\n\u003cli data-section-id=\"1g8wkgs\" data-start=\"2550\" data-end=\"2595\"\u003eSupport consistent nail driving performance\u003c\/li\u003e\n\u003cli data-section-id=\"8mtbw6\" data-start=\"2596\" data-end=\"2634\"\u003eImprove overall pneumatic efficiency\u003c\/li\u003e\n\u003cli data-section-id=\"13lapxq\" data-start=\"2635\" data-end=\"2720\"\u003eRestore the factory head valve sealing system \u003cspan class=\"\" data-state=\"closed\"\u003e\u003c\/span\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003chr data-start=\"2722\" data-end=\"2725\"\u003e\n\u003ch2 data-section-id=\"1cnbljb\" data-start=\"2727\" data-end=\"2764\"\u003eCommon Signs Replacement Is Needed\u003c\/h2\u003e\n\u003cp data-start=\"2766\" data-end=\"2808\"\u003eReplace the head valve seal if you notice:\u003c\/p\u003e\n\u003cul data-start=\"2810\" data-end=\"3021\"\u003e\n\u003cli data-section-id=\"1bnklq0\" data-start=\"2810\" data-end=\"2850\"\u003eAir leaking from the top of the nailer\u003c\/li\u003e\n\u003cli data-section-id=\"ha1zh6\" data-start=\"2851\" data-end=\"2874\"\u003eReduced driving power\u003c\/li\u003e\n\u003cli data-section-id=\"1bduzdm\" data-start=\"2875\" data-end=\"2907\"\u003eInconsistent firing or cycling\u003c\/li\u003e\n\u003cli data-section-id=\"1kenk8i\" data-start=\"2908\" data-end=\"2942\"\u003eWorn, cracked, or flattened seal\u003c\/li\u003e\n\u003cli data-section-id=\"18aush0\" data-start=\"2943\" data-end=\"2987\"\u003eAir escaping after the trigger is released\u003c\/li\u003e\n\u003cli data-section-id=\"9580pr\" data-start=\"2988\" data-end=\"3021\"\u003eSeal damaged during disassembly\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp data-start=\"3023\" data-end=\"3203\"\u003eA damaged head valve seal can prevent the nailer from maintaining proper air pressure, resulting in poor performance and continuous air leaks. \u003cspan class=\"\" data-state=\"closed\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003chr data-start=\"3205\" data-end=\"3208\"\u003e\n\u003ch2 data-section-id=\"10va281\" data-start=\"3210\" data-end=\"3241\"\u003eInstallation \u0026amp; Service Notes\u003c\/h2\u003e\n\u003cp data-start=\"3243\" data-end=\"3344\"\u003eDisconnect the nailer from the air supply and remove all fasteners before performing any maintenance.\u003c\/p\u003e\n\u003cp data-start=\"3346\" data-end=\"3943\"\u003eRemove the top cap to access the head valve assembly. Carefully remove the worn \u003cstrong data-start=\"3426\" data-end=\"3452\"\u003e904689 Head Valve Seal\u003c\/strong\u003e, clean the sealing surfaces, and inspect the head valve and cylinder for damage or debris. Install the new seal in the correct orientation, reassemble the head cap, and tighten the fasteners evenly according to the manufacturer's specifications. Reconnect the air supply and verify proper operation while checking for air leaks. If additional internal seals show signs of wear, consider installing the compatible \u003cstrong data-start=\"3866\" data-end=\"3889\"\u003e904949 Overhaul Kit\u003c\/strong\u003e during service. \u003cspan class=\"\" data-state=\"closed\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003cp data-start=\"3945\" data-end=\"4176\"\u003e\u003cstrong data-start=\"3945\" data-end=\"3959\"\u003eImportant:\u003c\/strong\u003e Head valve seals are intended for one-time installation. If the seal has been removed during servicing, replace it with a new OEM seal to maintain a reliable airtight connection. \u003cspan class=\"\" data-state=\"closed\"\u003e\u003c\/span\u003e\u003c\/p\u003e\n\u003chr data-start=\"4178\" data-end=\"4181\"\u003e\n\u003ch2 data-section-id=\"8fimbm\" data-start=\"4183\" data-end=\"4213\"\u003eMaintenance Recommendations\u003c\/h2\u003e\n\u003cul data-start=\"4215\" data-end=\"4689\" data-is-last-node=\"\" data-is-only-node=\"\"\u003e\n\u003cli data-section-id=\"196gqi3\" data-start=\"4215\" data-end=\"4300\"\u003eAdd pneumatic tool oil before each day of use unless your tool specifies otherwise.\u003c\/li\u003e\n\u003cli data-section-id=\"1a32vg8\" data-start=\"4301\" data-end=\"4358\"\u003eInspect the head valve area periodically for air leaks.\u003c\/li\u003e\n\u003cli data-section-id=\"1cp100q\" data-start=\"4359\" data-end=\"4427\"\u003eReplace worn seals promptly to maintain proper firing performance.\u003c\/li\u003e\n\u003cli data-section-id=\"18vxk98\" data-start=\"4428\" data-end=\"4476\"\u003eKeep the head assembly clean during servicing.\u003c\/li\u003e\n\u003cli data-section-id=\"rtxwml\" data-start=\"4477\" data-end=\"4530\"\u003eRebuild aging nailers with OEM seal kits as needed.\u003c\/li\u003e\n\u003cli data-section-id=\"1ps317d\" data-start=\"4531\" data-end=\"4689\" data-is-last-node=\"\"\u003eUse genuine OEM replacement parts to maintain factory fit, proper sealing, and long-term pneumatic nailer performance.\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/div\u003e\n\u003c\/section\u003e\n\u003c\/div\u003e","brand":"Porter Cable","offers":[{"title":"Default Title","offer_id":53578411671915,"sku":"904689","price":14.6,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0917\/9201\/5723\/files\/904689.jpg?v=1784606888","url":"https:\/\/generalsprayers.com\/products\/porter-cable-904689-head-valve-seal-genuine-oem-replacement-pneumatic-nailer-head-valve-seal","provider":"GeneralSprayers","version":"1.0","type":"link"}