Transom Seal Repair Kit – Fits MerCruiser Bravo 1, 2, 3 & Blackhawk (Replaces 30-803100T1, 8M0095485)

Transom Seal Repair Kit – Fits MerCruiser Bravo 1, 2, 3 & Blackhawk (Replaces 30-803100T1, 8M0095485)

This comprehensive repair kit contains all the necessary components to replace and reseal the bellows, gaskets, and water intake system on MerCruiser Bravo and Blackhawk sterndrive transoms manufactured from 1988 and newer. It is designed to meet or exceed original equipment specifications for a reliable, long-lasting repair.

This kit directly replaces Mercury/MerCruiser part numbers 30-803100T1 and 8M0095485, as well as aftermarket equivalents from Sierra (18-8212) and GLM (21961).

• Complete kit for a full overhaul of the transom sealing system.
• Engineered for a direct, OEM-equivalent fit and function.
• Constructed from durable neoprene/rubber bellows and high-quality metal components.

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 Drive Shaft Bellows (86840A05)
• 1 x Exhaust Tube Assembly (78458A1)
• 1 x Exhaust Bellows Assembly (18654A1/8M0124227)
• 1 x Bearing Assembly (30-862540A3)
• 1 x Shift Cable Bellows Assembly (74639A2)
• 1 x Water Hose (32-43437)
• 1 x Bravo Installation Kit (16755Q1)
• 1 x Rubber Bushing [for water intake]
• 1 x Bushing Retaining Tool
• 1 x Water Inlet Housing Gasket
• 2 x Screws (0.25 x 20 x 1.00)
• 1 x Hose End Insert
• 1 x Water Inlet Housing
• 1 x Installation Instruction Sheet

Installation Guide

1. Safety First: Disconnect the boat's battery and ensure the sterndrive is trimmed down to a safe working position.
2. Remove Sterndrive: Detach the sterndrive unit from the transom assembly according to your service manual's instructions. This will expose the bellows and gimbal housing.
3. Disconnect Old Components: Carefully cut and remove the old U-joint, exhaust, and shift cable bellows. Note the orientation of all clamps and hardware.
4. Inspect and Remove Bearing: Check the gimbal bearing for roughness or noise. If it needs replacement, use a slide hammer or bearing puller to remove it from the housing.
5. Clean Surfaces: Thoroughly clean all mounting surfaces on the transom assembly where gaskets and bellows will sit. Remove any old adhesive or debris.
6. Install New Bearing: Using a suitable bearing driver, carefully press the new gimbal bearing into the housing until it is fully seated. Ensure the grease hole is aligned correctly.
7. Install Bellows: Install the new shift cable bellow, followed by the U-joint (drive shaft) bellow and the exhaust bellow. Use new clamps and adhesive where specified.
8. Connect Hoses: Replace the raw water intake hose and any other small water hoses included in the kit, ensuring all connections are secure.
9. Reinstall Sterndrive: Carefully guide the sterndrive back into place, ensuring the driveshaft aligns with the gimbal bearing and engine coupler. Secure all mounting hardware to the proper torque.
10. Final Checks: Reconnect all systems and check for water leaks by running the engine with a water supply (flushing muffs). Check for proper steering and shifting operation.

Troubleshooting & FAQ

How do I confirm this kit fits my MerCruiser Bravo drive?
To ensure compatibility, check your sterndrive's serial number. This kit is designed for Bravo One, Two, and Three models with a serial number of 0B664190 or newer, and for Blackhawk models (1994-1995) with a serial number of 0D469859 or newer.

What are the common signs that my transom seals need to be replaced?
Key indicators of a failing transom seal include discovering water inside your boat's bilge area, finding water in the U-joint bellows, or hearing a grinding/whining noise from the gimbal bearing. You may also see visible cracks or deterioration on the rubber bellows during a visual inspection.

Does this kit include all the small clamps and seals I will need?
This kit contains the primary components required for a full transom reseal, including all bellows, the gimbal bearing, and essential gaskets. While it is comprehensive, we always recommend comparing the contents with your specific engine's diagram to confirm all necessary small clamps and O-rings are accounted for before starting the installation.

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.