MerCruiser Alpha Gen 1 Bellows Repair Kit – Fits R, MR, Alpha One (1983-1990) Sterndrives (Replaces 30-803097T1)

MerCruiser Alpha Gen 1 Bellows Repair Kit – Fits R, MR, Alpha One (1983-1990) Sterndrives

This is a complete, OEM-quality transom seal and bellows repair kit for MerCruiser R, MR, and Alpha One Generation 1 sterndrives manufactured from approximately 1976 to 1990. It provides a direct replacement for original parts, restoring the integrity of your sterndrive's transom assembly.

This comprehensive kit includes the driveshaft bellows, exhaust bellows, shift bellows, a new gimbal bearing, and all the necessary gaskets and hardware for a complete installation.

• Compatibility: Fits MerCruiser R, MR, Alpha One Gen 1 & Alpha One SS sterndrives.
• Installation: Designed as a direct replacement for OEM components.
• Complete Kit: Includes all three bellows, gimbal bearing, gaskets, and hardware.

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

Compatible Engine Models

Confirm your engine model/year in the table below. For Mercury owners, here’s a guide to help you identify your engine’s serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.

Technical Specifications

Package Contents

• 1 x U-Joint bellows assembly
• 1 x Exhaust Bellows
• 1 x Shift Bellows
• 1 x Gimbal Bearing
• 1 x Transom bell housing gasket set
• 1 x Water intake hoses (both 3/4" and 5/8" sizes included)
• 1 x Set of stainless steel hose clamps as required

Installation Guide

1. Position the sterndrive to the full "UP" or "TRAILER" position.
2. Disconnect the trim limit switch and trim sending unit wires. Remove the outdrive assembly from the bell housing.
3. Carefully remove the old shift cable bellows, exhaust bellows, and U-joint bellows. Note the orientation of the hose clamps.
4. Using a slide hammer or bearing puller, remove the old gimbal bearing from the transom assembly.
5. Thoroughly clean all mating surfaces on the bell housing and transom assembly, removing any old sealant or gasket material.
6. Align and press the new gimbal bearing into place using a bearing driver, ensuring it is properly seated.
7. Install the new shift cable bellows, ensuring a tight seal.
8. Fit the new exhaust bellows onto the bell housing and transom assembly.
9. Install the new U-joint bellows and the correct-sized water intake hose (3/4" or 5/8").
10. Securely fasten all new bellows with the provided stainless steel hose clamps.
11. Apply the new gaskets and reinstall the outdrive assembly, torquing all bolts to the manufacturer's specifications.
12. Reconnect all wiring, lower the drive, and check for any water leaks around the new seals before operating the vessel.

Troubleshooting & FAQ

How do I confirm this kit fits my Alpha One sterndrive?

This kit is for MerCruiser Alpha One Gen 1 sterndrives from 1983-1990 with serial numbers 6225577 and up. It also fits Alpha One SS models from 1986-1989 (S/N OA545004 & UP). Please verify your model and serial number range before ordering to ensure compatibility.

What are the signs that my bellows need replacing?

Common signs include visible cracks, perishing, or tears in the rubber bellows. Another critical indicator is discovering water in your bilge area, which could be coming from a leaking bellows. A grinding or roaring noise from the stern can indicate a failed gimbal bearing, which is often damaged when the U-joint bellows leaks.

Does this kit include everything I need for the job?

Yes, this is a comprehensive repair kit. It contains the u-joint, exhaust, and shift bellows, the gimbal bearing, a full transom gasket set, and new hose clamps. Importantly, it includes both 3/4" and 5/8" water hoses so you will have the correct size for your specific model.

OEM vs. Aftermarket?

This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.

How fast do you ship and how much does it cost?

We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.

What is your warranty and return policy?

This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.

Important Notes

• Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
• This product is an aftermarket replacement part and is not an OEM component.
• Professional installation is recommended to ensure safety and optimal performance.

Why Choose JLM MARINE?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.