Sierra 18-21005K Seal & Bearing Kit for Mercruiser Gimbal Bearing

The Sierra 18-21005K Seal & Bearing Kit is a replacement ball bearing and seal set built for Mercruiser gimbal bearing applications. It is designed as a direct-fit repair kit for boat owners and marine technicians who need to renew a worn or leaking gimbal bearing assembly without hunting down individual components separately. The kit pairs a metal ball bearing with matched seals so the bearing bore stays properly sealed against water intrusion, one of the most common causes of premature gimbal bearing failure on sterndrive boats.

Construction is metal for durability in the demanding marine environment, and the bearing is lubricated with grease to reduce friction and wear during operation. Sierra engineers its parts to meet or exceed the specification of the original equipment they replace, and the company supplies OEM engine manufacturers and boat builders with parts on a daily basis, so buyers can expect consistent fit and performance from the 18-21005K kit. Each kit is packaged as a complete, ready-to-install unit containing one bearing and its associated seal components.

This kit is intended for gimbal bearing service on Mercruiser sterndrive setups. Installers should confirm the bearing bore and shaft dimensions on their specific gimbal housing match this kit before ordering, as gimbal bearing kits are sized to a particular housing and drive combination.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-21005K
• Product Type: Seal & Bearing Kit
• Application: Mercruiser Gimbal Bearing
• Material: Metal
• Bearing Type: Ball Bearing
• Compatible Lubricant: Grease
• Item Dimensions: 4.5 x 2.75 x 5 inches
• Weight: 1.51 pounds
• Package Quantity: 1
• UPC: 808282187309
• Country of Origin: China

Frequently Asked Questions

What is included in the Sierra 18-21005K Seal & Bearing Kit? The Sierra 18-21005K kit includes one ball bearing and its matched seal components, packaged as a single ready-to-install seal and bearing kit for a package quantity of 1.

What is this kit used for? The 18-21005K is a seal and bearing kit for Mercruiser gimbal bearing service, replacing the bearing and seals in a gimbal bearing housing on a sterndrive boat.

What material is the Sierra 18-21005K made from? It is made of metal, with a ball bearing design lubricated with grease for smooth operation in marine use.

What are the dimensions of the Sierra 18-21005K Seal & Bearing Kit? The kit measures 4.5 x 2.75 x 5 inches and weighs 1.51 pounds.

Is the Sierra 18-21005K a genuine Sierra part or aftermarket? 18-21005K is a Sierra-branded seal and bearing kit engineered to meet or exceed the specification of the original equipment part it replaces.

What type of bearing does this kit use? This kit uses a ball bearing, designated bearing number 18-21005K, matched with seals for the gimbal bearing bore.

What lubricant should be used with the 18-21005K bearing? The bearing in the 18-21005K kit is compatible with standard marine grease lubricant.

Where is the Sierra 18-21005K manufactured? The country of origin for the 18-21005K Seal & Bearing Kit is China.

How many bearings come in one 18-21005K kit? Each 18-21005K kit has a package quantity of 1, containing a single seal and bearing set.

Does the Sierra 18-21005K require special tools to install? The kit is a standard press-fit seal and bearing replacement for a gimbal bearing housing; installers should verify bore and shaft dimensions match their gimbal housing before installing the 18-21005K.