MerCruiser Transom Bellows Kit – Fits Bravo 1, 2, 3 & Blackhawk Stern Drives
This transom service kit includes all the necessary components to replace the bellows, gimbal bearing, and seals on MerCruiser Bravo and Blackhawk stern drives. It is designed to meet or exceed OEM specifications for a reliable, direct-fit installation.
This kit is compatible with MerCruiser Bravo I, II, and III stern drives (1998 and newer, serial numbers 0B664190 and up) and Blackhawk stern drives (1994-1995, serial numbers 0D469859 and up). It is a direct replacement for MerCruiser part numbers 30-803100T1 and 8M0095485.
- Includes U-joint, exhaust, and shift cable bellows.
- Features a pre-greased, sealed gimbal bearing for simplified installation.
- Components are made from marine-grade neoprene and stainless steel for durability.
Part Number Cross-Reference
Use this table to confirm equivalent part numbers across OEM and aftermarket brands.
| Brand |
Part Number |
| MerCruiser |
30-803100T1, 8M0095485 |
| Sierra |
18-8219, 18-8212-1 |
| GLM |
21965 |
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.
| Brand |
Model |
Years |
OEM Part No. |
Notes |
| MerCruiser |
Bravo I |
1998-present |
30-803100T1/8M0095485 |
Serial number 0B664190 & up |
| MerCruiser |
Bravo II |
1998-present |
30-803100T1/8M0095485 |
Serial number 0B664190 & up |
| MerCruiser |
Bravo III |
1998-present |
30-803100T1/8M0095485 |
Serial number 0B664190 & up |
| MerCruiser |
Blackhawk |
1994-1995 |
30-803100T1/8M0095485 |
Serial number 0D469859 & up |
Technical Specifications
| Specification |
Value |
| Product Type |
Transom Bellows Service Kit |
| Installation |
Direct OEM replacement |
| Connection |
Direct mount to transom assembly |
| Housing Material |
CR Neoprene bellows, SS304 clips and clamps |
| Housing Color |
Black |
| Fitting Type |
Marine stern drive transom assembly |
| Other Technical Attributes |
Marine engine grade O-rings |
Package Contents
- 1 x Gimbal Bearing with Gimbal Housing Seal (Replaces 41802)
- 1 x U-Joint Bellow (Replaces 86840A3/86840A05)
- 1 x Shift Cable Bellow (Replaces 74639)
- 1 x Bell Housing Exhaust Bellow (Replaces 18654A1)
- 1 x Exhaust Tube (Replaces 78458A1)
- 1 x Water Intake Hose
- 1 x Outdrive Gasket Set
- 1 x Gimbal Housing Oil Seal (Replaces 16755Q1)
- 1 x Gimbal Housing Seal (Replaces 41802)
- 1 x Insert Driver (Replaces 41674)
- 1 x Lever (Replaces 45518A3)
- 1 x Guide (Replaces 43433)
- 1 x Insert (Replaces 14705)
- 1 x Shift Cable Wrapping (Replaces 38473)
Installation Guide
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Safety First: Disconnect the battery and ensure the boat is securely positioned on a trailer or lift.
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Remove Stern Drive: Place the drive in the forward gear. Remove the trim rams and tilt the drive up to access and remove the main mounting nuts. Carefully slide the stern drive off the transom assembly.
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Remove Old Components: Remove the old exhaust, u-joint, and shift cable bellows by cutting the old clamps. Use a slide hammer or puller to remove the old gimbal bearing.
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Clean Surfaces: Thoroughly clean all mounting surfaces on the transom assembly, removing any old adhesive, sealant, or corrosion.
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Install New Bearing: Use a bearing driver to carefully install the new gimbal bearing. Ensure it is properly seated and aligned.
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Install New Bellows: Install the new shift cable, u-joint, and exhaust bellows. Use bellow adhesive on contact surfaces and secure all new clamps tightly.
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Reinstall Stern Drive: Guide the drive shaft through the new gimbal bearing and bellows. Re-attach all hardware and torque to the manufacturer's specifications.
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Final Checks: Reconnect the battery. Lower the stern drive and check for water leaks around the new bellows. Test the shifting and steering for proper operation.
Troubleshooting & FAQ
Q: How do I confirm this kit fits my MerCruiser stern drive?
A: This kit is designed for MerCruiser Bravo I, II, and III stern drives made in 1998 or later (serial number 0B664190 and up) and Blackhawk drives from 1994-1995. Please verify your drive model and serial number against the compatibility list before ordering. You can also cross-reference the OEM part numbers 30-803100T1 or 8M0095485.
Q: What are the signs that my transom bellows need replacing?
A: Common signs of failure include visible cracks or tears in the rubber, water entering the bilge area, or a stiff or grinding feeling when turning the steering wheel, which could indicate a failed gimbal bearing due to water intrusion.
Q: How often should the transom bellows be inspected or replaced?
A: Bellows should be inspected annually for cracks, stiffness, or signs of wear. A full replacement is typically recommended every 5-7 years, or immediately if any damage is found, to prevent catastrophic water damage to the gimbal bearing, u-joints, and transom assembly.
Q: OEM vs. Aftermarket?
A: 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.
Q: How fast do you ship and how much does it cost?
A: 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.
Q: What is your warranty and return policy?
A: 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?
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Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
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Fast Global Shipping: Free delivery worldwide in 5–15 days.
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Direct from Manufacturer: Competitive pricing without compromising quality.