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

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

This comprehensive transom service kit provides all the necessary components to repair and reseal the bell housing on MerCruiser sterndrives. It is designed for MerCruiser R, MR, and Alpha One (Gen 1) models (1983–1990) with serial numbers 6225577 and up, as well as MerCruiser Alpha One SS models (1986–1989) with serial numbers 0A545004 and up.

This kit serves as a direct replacement for multiple OEM and aftermarket part numbers, including Mercury/MerCruiser 30-803097T1, Sierra 18-2601-1, and GLM 21950, ensuring wide compatibility for the specified models.

• Includes a complete set of U-joint, exhaust, and shift cable bellows.
• Features a new gimbal bearing, water hoses, and a full gasket and O-ring kit.
• Components are made from durable neoprene rubber and stainless steel for longevity in marine environments.

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

This comprehensive kit includes everything needed for a complete transom bellows and gimbal bearing service:

• 1 x U-Joint Bellows with clamps (Replaces 60932A4)
• 1 x Exhaust Bellows with clamps (Replaces 18654A1)
• 1 x Shift Cable Bellows with clamps (Replaces 74639)
• 1 x Gimbal Bearing (Replaces 30-60792A4)
• 1 x Water Hose 3/4" (Replaces 32-41725)
• 1 x Water Hose 5/8" (Replaces 32-32461)
• 1 x Gasket Kit (Replaces 27-94996T2), which includes:
  • 1 x Bell Housing Gasket
  • 1 x O-Ring (Replaces 25-33504)
  • 1 x O-Ring (Replaces 25-35027)
  • 2 x O-Rings (Replaces 25-25439)
• 1 x Shift Cable Guide (Replaces 43433)
• 1 x Shift Cable Insert (Replaces 14705)
• 1 x Shift Cable Wrapping (Replaces 38473)
• 1 x Bell Housing Shaft Lever (Replaces 45518A3)
• 1 x Gimbal Housing Oil Seal (Replaces 26-88416)
• 1 x Gimbal Housing Seal (Replaces 41802)

Installation Guide

Professional installation is highly recommended for this kit. The following steps provide a general overview of the process:

1. Disconnect the battery and safely trim the sterndrive to the full "up" position.
2. Remove the sterndrive assembly from the bell housing. This involves disconnecting trim cylinders, speedo tubes, and shift cables.
3. Remove the bell housing from the transom assembly to gain access to the bellows and gimbal bearing.
4. Carefully cut and remove the old U-joint, exhaust, and shift cable bellows, and their clamps.
5. Use a slide hammer or bearing puller to extract the old gimbal bearing from the housing.
6. Thoroughly clean all mating surfaces on the transom and bell housing, removing old sealant and debris.
7. Install the new gimbal bearing and oil seal into the gimbal housing, ensuring proper depth and alignment.
8. Install the new U-joint, exhaust, and shift cable bellows. Use a bellows expander tool and secure them with the provided stainless steel clamps.
9. Replace all gaskets and O-rings on the bell housing before reinstalling it onto the transom assembly. Torque all fasteners to manufacturer specifications.
10. Re-attach the sterndrive assembly, connecting all hydraulic lines, cables, and linkages.
11. Check for proper shift operation and trim functionality before starting the engine.
12. CRITICAL: After launching, check immediately for any water leaks around the transom assembly.

Troubleshooting & FAQ

How do I confirm this kit fits my MerCruiser sterndrive?
Verify your sterndrive model and, most importantly, its serial number. This kit is specifically for MerCruiser R, MR, and Alpha One (Gen 1) drives with serial numbers 6225577 and up, and Alpha One SS drives with serial numbers 0A545004 and up. Do not use this kit if your serial number is outside these ranges.

What are the signs my transom bellows need replacing?
Common symptoms of failing bellows include finding water in your boat's bilge, hearing grinding or roaring noises from the gimbal bearing (indicating water intrusion), or seeing visible cracks, holes, or stiffness in the rubber bellows during inspection.

How often should I replace the transom bellows?
As a preventative measure, it is recommended to inspect bellows annually and replace the entire kit every 5-7 years. For boats operated in saltwater or harsh environments, more frequent replacement may be necessary.

Is special equipment needed for installation?
Yes, this is an advanced repair. Proper installation requires specialized tools such as a gimbal bearing puller/installer, a hinge pin tool to remove the bell housing, and a bellows expander tool to install the exhaust bellows without damaging it.

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.