Description
Product Overview
The NorthBoat Transom Seal Bellows Kit is engineered for MerCruiser Alpha I Gen II sterndrives, offering a comprehensive rubber sealing system that safeguards the exhaust, U‑joints and shift cable from water intrusion. Constructed from high‑grade marine‑grade rubber, each bellows component delivers flexibility and resilience, allowing the sterndrive to pivot and tilt without compromising the seal. The kit includes a U‑joint bellows, exhaust bellows, shift cable bellows, a 3/4 inch water hose, gimbal bearing, gasket set, O‑rings and a hinge pin installation tool, providing everything needed for a full replacement. Dimensions of the package are 12.24 x 7.2 x 6.06 inches and the total weight is 4.16 pounds, making handling straightforward.
Usage
Designed for recreational and professional boat owners, this kit is ideal for vessels equipped with MerCruiser Alpha I Gen II sterndrives from 1991 onward. Install the bellows during routine maintenance or when signs of wear appear, such as water leakage around the transom area. The rubber construction tolerates the harsh marine environment, resisting UV, ozone and saltwater corrosion. Regular inspection every two years and replacement with this kit ensures the drivetrain remains dry, reducing the risk of corrosion and maintaining optimal thrust and handling. 
Why Choose Us
NorthBoat combines decades of marine engineering expertise with rigorous quality control. Each bellows is molded to exact OEM specifications (GLM 21960, Sierra 18‑8206) guaranteeing a perfect fit and seamless integration with existing components. The kit’s all‑inclusive packaging eliminates the need for additional purchases, saving time and cost. Our rubber material is tested for flexibility at low temperatures and durability at high temperatures, ensuring reliable performance across a wide range of operating conditions. Backed by a positive customer rating of 3.6 stars and a strong ranking in the automotive replacement category, this kit reflects trusted reliability.
Key Features
- Marine‑grade rubber bellows provide superior water resistance and flexibility.
- Complete kit includes all bellows, gaskets, O‑rings and installation tool.
- Exact OEM fit for MerCruiser Alpha I Gen II models (1991 and newer).
- Designed to protect exhaust, U‑joints and shift cable from corrosion.
- Easy installation reduces downtime and maintenance costs.
FAQ
What boat models are compatible with this kit?
The kit fits MerCruiser Alpha I Gen II sterndrives from 1991 onward, covering serial numbers starting at 0D469859 and up.
How often should the bellows be replaced?
It is recommended to inspect the bellows annually and replace the entire kit every two years, or sooner if signs of wear or water leakage are observed.
Do I need additional tools for installation?
All necessary components, including a hinge pin tool, are included in the package. Standard hand tools such as wrenches and screwdrivers are sufficient for installation.
Can the rubber bellows handle extreme temperatures?
Yes, the marine‑grade rubber is formulated to remain flexible in cold water and resist degradation in high‑heat conditions, ensuring reliable sealing in diverse climates.
Is this kit covered by a warranty?
NorthBoat offers a one‑year limited warranty against manufacturing defects, providing peace of mind for your investment.




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