{"product_id":"upper-unit-seal-kit-fits-mercruiser-alpha-one-gen-i-r-mr-mc-1-replaces-26-32511a1-18-2648","title":"Upper Unit Seal Kit – Fits MerCruiser Alpha One Gen I, R, MR, MC-1 (Replaces 26-32511A1, 18-2648)","description":"\u003cstyle\u003e\n  .ss-table-wrap { overflow-x:auto; -webkit-overflow-scrolling:touch; }\n  table.ss-table { width:100%; border-collapse:collapse; min-width:640px; }\n  table.ss-table th, table.ss-table td {\n    padding:10px 12px; border:1px solid #e5e7eb; text-align:left; vertical-align:top;\n  }\n  table.ss-table th {\n    white-space:nowrap;\n    word-break:normal;\n    letter-spacing:normal;\n    font-weight:600;\n    background:#f8fafc;\n  }\n  @media (max-width:480px){\n    table.ss-table th, table.ss-table td { padding:8px 10px; font-size:14px; }\n  }\n\u003c\/style\u003e\n\n\u003ch2\u003eProduct Details\u003c\/h2\u003e\n\u003cp\u003eThis \u003cstrong\u003eUpper Unit Seal Kit\u003c\/strong\u003e is designed for MerCruiser Alpha One Gen I, R, MR, and MC-1 sterndrive upper units. It delivers reliable sealing performance for a broad range of MerCruiser models including 1A, 1B, 1C, and EZ Shift configurations, ensuring proper protection against water intrusion and fluid leakage.\u003c\/p\u003e\n\u003cp\u003eThis aftermarket kit directly replaces Mercury Marine\/Quicksilver part number 26-32511A1, as well as GLM 87500 and Sierra Marine 18-2648.\u003c\/p\u003e\n\u003cul\u003e\n  \u003cli\u003eComplete seal replacement for upper unit maintenance and rebuild\u003c\/li\u003e\n  \u003cli\u003eCompatible with MerCruiser sterndrive Alpha One Gen I series\u003c\/li\u003e\n  \u003cli\u003eEngineered to OEM specifications for secure fitment and durability\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003ePart Number Matrix\u003c\/h2\u003e\n\u003cp\u003eUse this matrix to confirm equivalent references across OEM and aftermarket.\u003c\/p\u003e\n\u003cdiv class=\"ss-table-wrap\"\u003e\n  \u003ctable class=\"ss-table\" aria-label=\"Part Number Matrix\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth\u003eBrand\u003c\/th\u003e\n        \u003cth\u003ePart Number\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMercury Marine \/ Quicksilver\u003c\/td\u003e\n        \u003ctd\u003e26-32511A1\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eSierra Marine\u003c\/td\u003e\n        \u003ctd\u003e18-2648\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eGLM\u003c\/td\u003e\n        \u003ctd\u003e87500\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eEngine \u0026amp; Model Compatibility\u003c\/h2\u003e\n\u003cp\u003eConfirm your engine model\/year in the table below.\u003c\/p\u003e\n\u003cdiv class=\"ss-table-wrap\"\u003e\n  \u003ctable class=\"ss-table\" aria-label=\"Engine \u0026amp; Model Compatibility\"\u003e\n    \u003cthead\u003e\n      \u003ctr\u003e\n        \u003cth\u003eBrand\u003c\/th\u003e\n        \u003cth\u003eModel\u003c\/th\u003e\n      \u003c\/tr\u003e\n    \u003c\/thead\u003e\n    \u003ctbody\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMerCruiser\u003c\/td\u003e\n        \u003ctd\u003e1A\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMerCruiser\u003c\/td\u003e\n        \u003ctd\u003e1B\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMerCruiser\u003c\/td\u003e\n        \u003ctd\u003e1C\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMerCruiser\u003c\/td\u003e\n        \u003ctd\u003eEZ Shift\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMerCruiser\u003c\/td\u003e\n        \u003ctd\u003eMC-1\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMerCruiser\u003c\/td\u003e\n        \u003ctd\u003eR\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMerCruiser\u003c\/td\u003e\n        \u003ctd\u003eMR\u003c\/td\u003e\n      \u003c\/tr\u003e\n      \u003ctr\u003e\n        \u003ctd\u003eMerCruiser\u003c\/td\u003e\n        \u003ctd\u003eAlpha One Gen I\u003c\/td\u003e\n      \u003c\/tr\u003e\n    \u003c\/tbody\u003e\n  \u003c\/table\u003e\n\u003c\/div\u003e\n\n\u003ch2\u003eTechnical Specs\u003c\/h2\u003e\n\u003cdl\u003e\n  \u003cdt\u003eApplication\u003c\/dt\u003e\n  \u003cdd\u003eMerCruiser sterndrive upper units\u003c\/dd\u003e\n  \u003cdt\u003eOEM Replacement\u003c\/dt\u003e\n  \u003cdd\u003e26-32511A1\u003c\/dd\u003e\n  \u003cdt\u003ePart Type\u003c\/dt\u003e\n  \u003cdd\u003eSeal kit\u003c\/dd\u003e\n  \u003cdt\u003eUnit\u003c\/dt\u003e\n  \u003cdd\u003eUpper unit\u003c\/dd\u003e\n\u003c\/dl\u003e\n\n\u003ch2\u003eWhat's in the Box\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003eComplete upper unit seal kit with all required gaskets and seals\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003col\u003e\n  \u003cli\u003eDisconnect battery and remove upper unit from lower unit per manufacturer service manual.\u003c\/li\u003e\n  \u003cli\u003eDrain all lubricant from the upper gearcase and inspect for metal debris or contamination.\u003c\/li\u003e\n  \u003cli\u003eRemove old seals and gaskets carefully, cleaning all mating surfaces thoroughly with solvent.\u003c\/li\u003e\n  \u003cli\u003eInspect shafts, bearings, and housings for wear or damage; replace components as needed.\u003c\/li\u003e\n  \u003cli\u003eInstall new seals using the appropriate seal driver or socket to avoid cocking or damage.\u003c\/li\u003e\n  \u003cli\u003eLubricate seal lips lightly with gear oil before assembly.\u003c\/li\u003e\n  \u003cli\u003eReassemble upper unit, ensuring all fasteners are torqued to specification.\u003c\/li\u003e\n  \u003cli\u003eRefill with manufacturer-recommended sterndrive gear lubricant to proper level.\u003c\/li\u003e\n  \u003cli\u003eReinstall upper unit onto lower unit and verify smooth engagement.\u003c\/li\u003e\n  \u003cli\u003eRun engine in neutral and check for leaks around all seal areas.\u003c\/li\u003e\n  \u003cli\u003eTest shift operation and perform a water trial under normal operating conditions.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch2\u003eTroubleshooting \u0026amp; FAQ\u003c\/h2\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eHow do I know if my upper unit seals need replacement?\u003c\/summary\u003e\n  \u003cp\u003eSigns include visible gear oil leaking from the upper unit, milky or contaminated gear oil indicating water intrusion, or unusual noise during operation. Regular inspection during seasonal maintenance is recommended.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWill this kit fit both R and MR drive models?\u003c\/summary\u003e\n  \u003cp\u003eYes, this seal kit is engineered to fit MerCruiser R, MR, MC-1, and Alpha One Gen I upper units. Always verify your drive serial number and model designation before ordering.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eDo I need special tools to install this seal kit?\u003c\/summary\u003e\n  \u003cp\u003eA seal driver set, torque wrench, and basic hand tools are recommended. Some seals may require a press or appropriately sized socket for safe installation without damage.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eCan I reuse the old seals if they look okay?\u003c\/summary\u003e\n  \u003cp\u003eNo. Seals are designed for single use and lose their sealing capability once removed. Always replace with new seals during any upper unit service to prevent leaks.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWhat type of gear oil should I use after installing the seal kit?\u003c\/summary\u003e\n  \u003cp\u003eUse Mercury\/Quicksilver Premium or High Performance gear lubricant as specified in your owner's manual. Capacity and viscosity vary by model, so consult your service documentation.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eHow often should upper unit seals be replaced?\u003c\/summary\u003e\n  \u003cp\u003eReplace seals whenever the upper unit is disassembled for service, or if leaks or contamination are detected. Typical service intervals range from 100–300 hours depending on operating conditions.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eOEM vs. Aftermarket?\u003c\/summary\u003e\n  \u003cp\u003eThis listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eShipping speed \u0026amp; cost\u003c\/summary\u003e\n  \u003cp\u003eWe ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.\u003c\/p\u003e\n\u003c\/details\u003e\n\u003cdetails\u003e\n  \u003csummary\u003eWarranty \u0026amp; returns\u003c\/summary\u003e\n  \u003cp\u003eCovered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused \u0026amp; in original condition). See our policy page or reach out for instructions.\u003c\/p\u003e\n\u003c\/details\u003e\n\n\u003ch2\u003eSafety \u0026amp; Important Info\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003eVerify images\/specifications against your original part. If anything differs—even if your model appears compatible—do not purchase.\u003c\/li\u003e\n  \u003cli\u003eThis is an aftermarket replacement, not an OEM component.\u003c\/li\u003e\n  \u003cli\u003eProfessional installation is recommended for safety and performance.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eAbout Sea Sierra\u003c\/h2\u003e\n\u003cul\u003e\n  \u003cli\u003ePro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.\u003c\/li\u003e\n  \u003cli\u003eFast Global Fulfillment — Free standard delivery to most regions in 5–15 days.\u003c\/li\u003e\n  \u003cli\u003eManufacturer-Direct Value — Fair pricing without compromising on materials or QC.\u003c\/li\u003e\n\u003c\/ul\u003e","brand":"SeaSierra","offers":[{"title":"Default Title","offer_id":51025816748347,"sku":"24SK445","price":18.99,"currency_code":"USD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0826\/8673\/8747\/files\/12_ef692db8-e65e-48f2-95d4-adf56ba1baec.jpg?v=1773220845","url":"https:\/\/seasierra.com\/products\/upper-unit-seal-kit-fits-mercruiser-alpha-one-gen-i-r-mr-mc-1-replaces-26-32511a1-18-2648","provider":"SeaSierra","version":"1.0","type":"link"}