{"product_id":"sierra-gimbal-bearing-18-21006-mercruiser-bravo-gen-ii","title":"Sierra Gimbal Bearing 18-21006 | MerCruiser Bravo \u0026 Gen II Sterndrive","description":"\u003ch2\u003eSierra Gimbal Bearing 18-21006 — MerCruiser Bravo \u0026amp; Gen II Sterndrive\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003ePart Number:\u003c\/strong\u003e 18-21006 (Sierra)  |  \u003cstrong\u003eBrand:\u003c\/strong\u003e Sierra  |  \u003cstrong\u003eOEM Cross-Reference:\u003c\/strong\u003e MerCruiser 21006\u003c\/p\u003e\n\u003cp\u003eThe Sierra \u003cstrong\u003e18-21006\u003c\/strong\u003e is a direct-replacement gimbal bearing engineered to OEM fit and dimensional specifications for MerCruiser Bravo One, Bravo Two, Bravo Three, and Gen II sterndrive applications. The gimbal bearing supports the driveshaft at the transom plate and allows the sterndrive unit to pivot smoothly through its full range of steering and trim movement. A worn or failed gimbal bearing causes grinding noise at the transom, rough steering, and — if ignored — accelerated wear to the bellows assembly, driveshaft, and u-joints.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eWeight:\u003c\/strong\u003e 533 g  |  \u003cstrong\u003eQuantity:\u003c\/strong\u003e 1 bearing per package\u003c\/p\u003e\n\n\u003ch2\u003eCompatible Applications\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eMerCruiser Bravo One sterndrive (OEM gimbal bearing ref \u003cstrong\u003e21006\u003c\/strong\u003e)\u003c\/li\u003e\n\u003cli\u003eMerCruiser Bravo Two sterndrive (OEM gimbal bearing ref \u003cstrong\u003e21006\u003c\/strong\u003e)\u003c\/li\u003e\n\u003cli\u003eMerCruiser Bravo Three sterndrive (OEM gimbal bearing ref \u003cstrong\u003e21006\u003c\/strong\u003e)\u003c\/li\u003e\n\u003cli\u003eMerCruiser Gen II sterndrive applications specifying gimbal bearing \u003cstrong\u003e21006\u003c\/strong\u003e\n\u003c\/li\u003e\n\u003c\/ul\u003e\n\u003cp\u003e\u003cstrong\u003eFitment Notice:\u003c\/strong\u003e The Bravo\/Gen II gimbal bearing (\u003cstrong\u003e18-21006\u003c\/strong\u003e) and the Alpha One gimbal bearing are \u003cem\u003enot interchangeable\u003c\/em\u003e. Confirm your drive generation and existing OEM bearing number before ordering. For Alpha One and earlier applications, see \u003ca href=\"\/products\/8131388211236\"\u003eGimbal Bearing 47-21001\u003c\/a\u003e.\u003c\/p\u003e\n\n\u003ch2\u003eSpecifications\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eManufacturer Part Number:\u003c\/strong\u003e 18-21006\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eBrand:\u003c\/strong\u003e Sierra\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eProduct Type:\u003c\/strong\u003e Gimbal Bearing — complete replacement unit\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eSystem:\u003c\/strong\u003e Sterndrive transom \/ gimbal housing assembly\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eWeight:\u003c\/strong\u003e 533 g\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eOEM Cross-Reference:\u003c\/strong\u003e MerCruiser 21006\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eService Interval\u003c\/h2\u003e\n\u003cp\u003eInspect the gimbal bearing any time the sterndrive is removed. Replace when any of the following are observed:\u003c\/p\u003e\n\u003cul\u003e\n\u003cli\u003eGrinding, rumbling, or clicking noise at the transom during operation or steering\u003c\/li\u003e\n\u003cli\u003eRough, binding, or notchy sterndrive pivot movement\u003c\/li\u003e\n\u003cli\u003eVisible pitting, corrosion, or roughness on the bearing surfaces\u003c\/li\u003e\n\u003cli\u003eDuring bellows replacement service — labor overlap makes simultaneous bearing replacement cost-effective\u003c\/li\u003e\n\u003cli\u003eAfter any significant impact to the drive or transom assembly\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eInstallation Notes\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003eRemove the sterndrive unit and transom assembly to access the gimbal ring\u003c\/li\u003e\n\u003cli\u003eInspect the gimbal housing bore, bellows, inner and outer u-joints, and driveshaft seal surfaces during the same service\u003c\/li\u003e\n\u003cli\u003ePress the new bearing into the gimbal ring to the correct depth — use the manufacturer-specified bearing installation driver to avoid damage to the bearing race\u003c\/li\u003e\n\u003cli\u003eReplace the bellows set and all seals as a complete assembly when performing gimbal bearing service\u003c\/li\u003e\n\u003cli\u003eGrease bearing contact surfaces and pivot pins per the engine manufacturer's service manual specification before reassembly\u003c\/li\u003e\n\u003cli\u003eTorque all fasteners to specification\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eCross-Reference Part Numbers\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\n\u003cstrong\u003eSierra:\u003c\/strong\u003e 18-21006\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eMerCruiser OEM:\u003c\/strong\u003e 21006\u003c\/li\u003e\n\u003cli\u003e\n\u003cstrong\u003eDistributor\/Catalog SKU:\u003c\/strong\u003e 47-21006\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eRelated Products\u003c\/h2\u003e\n\u003cul\u003e\n\u003cli\u003e\u003ca href=\"\/products\/8131388211236\"\u003eGimbal Bearing 47-21001 — Alpha One \/ Volvo Penta Applications\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/products\/8131432087588\"\u003eMerCruiser Gimbal Bearing Kit 879194A01 — Alpha One\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/products\/8131432120356\"\u003eMerCruiser Gimbal Bearing Kit 879194A02 — Alpha One\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/products\/8131416424484\"\u003eMerCruiser Gimbal Housing Bushing Kit 805041A2\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/products\/8131402006564\"\u003eMerCruiser Gimbal Housing Lock Nut 11-34087\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/products\/8131437723684\"\u003eMerCruiser Bellows Assembly 8M0062406\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/products\/8131441524772\"\u003eMerCruiser Bellows Assembly 8M0124227\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/products\/11119998795812\"\u003eSierra Transom Seal Kit 47-8205\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/products\/11119998828580\"\u003eSierra Transom Seal Kit 47-82061\u003c\/a\u003e\u003c\/li\u003e\n\u003cli\u003e\u003ca href=\"\/products\/8131401809956\"\u003eMerCruiser Lower Unit Seal Kit 26-33144A2\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch2\u003eParts Desk Insights\u003c\/h2\u003e\n\u003cp\u003e\u003cstrong\u003eBest use case:\u003c\/strong\u003e The \u003cstrong\u003e18-21006\u003c\/strong\u003e is the right bearing for any Bravo or Gen II sterndrive transom service. If you're already pulling the drive for bellows replacement, always inspect — and in most cases replace — the gimbal bearing at the same time. The labor to access it is identical, and a failed bearing discovered later means a full repeat teardown.\u003c\/p\u003e\n\u003cp\u003e\u003cstrong\u003eCommon issue:\u003c\/strong\u003e The most frequent ordering error is confusing Bravo and Alpha generation bearings. Customers often search by engine rather than drive model — the gimbal bearing is specific to the \u003cem\u003esterndrive unit generation\u003c\/em\u003e, not the engine. If your boat has a MerCruiser engine but an Alpha One drive, you need \u003ca href=\"\/products\/8131388211236\"\u003e47-21001\u003c\/a\u003e, not this bearing. Always confirm the drive model plate on the transom assembly before ordering.\u003c\/p\u003e","brand":"LNS","offers":[{"title":"Default Title","offer_id":51037541433380,"sku":"47-21006","price":236.09,"currency_code":"CAD","in_stock":true}],"thumbnail_url":"\/\/cdn.shopify.com\/s\/files\/1\/0743\/5799\/7604\/files\/47-21006.jpg?v=1783568599","url":"https:\/\/marisolmarine.com\/products\/sierra-gimbal-bearing-18-21006-mercruiser-bravo-gen-ii","provider":"Marisol Marine Company","version":"1.0","type":"link"}