Transom Bellows Seal Kit – Fits MerCruiser Bravo 1, 2, 3 Drives (Replaces 30-803100T1, 8M0095485)
Transom Bellows Seal Kit – Fits MerCruiser Bravo 1, 2, 3 Drives (Replaces 30-803100T1, 8M0095485) is backordered and will ship as soon as it is back in stock.
Couldn't load pickup availability
Worry-free returns
Worry-free returns
You may return most new, unopened items within 7 days of delivery for a full refund. We'll also pay the return shipping costs if the return is a result of our error (you received an incorrect or defective item, etc.).
You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).
If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.
Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Transom Bellows Seal Kit – Fits MerCruiser Bravo 1, 2, 3 Drives (Re...
Product Details
This complete Transom Bellows Seal Kit – Fits MerCruiser Bravo 1, 2, 3 Drives (Replaces 30-803100T1, 8M0095485) is designed for MerCruiser Bravo I, II, and III stern drives from 1988 and newer (serial number 0B664190 and up), as well as Blackhawk models from 1994–1995 (serial number 0D469859 and up).
It directly replaces Mercury/MerCruiser OEM parts 30-803100T1 and 8M0095485, and serves as an aftermarket interchange for Sierra 18-8212/18-8219, GLM 21961/21965, and Mallory 9-72903/9-72905.
- Kit includes all essential bellows, gaskets, clamps, and a gimbal bearing for a comprehensive service.
- Designed for direct aftermarket or OEM replacement with no modifications needed.
- Covered by a 1-year aftermarket warranty for peace of mind.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury/MerCruiser | 30-803100T1 |
| Mercury/MerCruiser | 8M0095485 |
| Sierra | 18-8212 (greasable bearing) |
| Sierra | 18-8219 (sealed bearing) |
| GLM | 21961 |
| GLM | 21965 |
| Mallory | 9-72903 |
| Mallory | 9-72905 |
| Redline | RL21961 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
Fitment is confirmed for MerCruiser Bravo and Blackhawk models within the specified serial number ranges.
| Brand | Model | Application | Years | OEM Part No. |
|---|---|---|---|---|
| MerCruiser | Bravo I | Stern Drive | 1988 & up (SN: 0B664190 & up) | 30-803100T1, 8M0095485 |
| MerCruiser | Bravo II | Stern Drive | 1988 & up (SN: 0B664190 & up) | 30-803100T1, 8M0095485 |
| MerCruiser | Bravo III | Stern Drive | 1988 & up (SN: 0B664190 & up) | 30-803100T1, 8M0095485 |
| MerCruiser | Blackhawk | Stern Drive | 1994–1995 (SN: 0D469859 & up) | 30-803100T1, 8M0095485 |
Technical Specs
- Product Type
- Transom Seal/Bellows Repair Kit
- Installation
- OEM or Aftermarket Replacement
- Housing Material
- Rubber/Neoprene, Metal (Gimbal Bearing)
- Warranty
- 1 Year (Aftermarket)
What’s in the Box
- 1 x U-Joint Bellows (86840A05)
- 1 x Exhaust Bellows Assembly (18654A1)
- 1 x Exhaust Tube Assembly (78458A1)
- 1 x Shift Cable Bellows Assembly (74639A2)
- 1 x Gimbal Bearing Assembly (30-862540A3)
- 1 x Water Inlet Hose (32-43437)
- 1 x Bravo Installation Kit (16755Q1)
- 1 x Set of Bellows Clamps and Hardware
Installation Notes
- Disconnect the battery and trim the drive to the full "up" position.
- Remove the drive assembly from the bell housing.
- Carefully cut and remove the old U-joint, exhaust, and shift cable bellows, noting clamp positions.
- Inspect the gimbal housing for wear or damage and remove the old gimbal bearing.
- Install the new gimbal bearing using an appropriate driver tool.
- Install the new shift cable bellow, ensuring a tight seal.
- Install the new exhaust and U-joint bellows, securing all clamps tightly.
- Install the new water inlet hose.
- Reinstall the drive assembly, checking for proper alignment and shift cable operation.
- Lower the drive and test for leaks in a controlled environment before open water use.
Troubleshooting & FAQ
How do I know if this kit fits my Bravo drive?
This kit fits MerCruiser Bravo I, II, and III models from 1988 and newer with a serial number of 0B664190 and higher. It also fits Blackhawk drives from 1994-1995 (SN 0D469859+). Always verify your serial number to ensure compatibility.
What are the signs my transom bellows need replacing?
Common failure signs include visible cracks or tears in the rubber, water entering the bilge area, a stiff or noisy gimbal bearing, or difficulty shifting. Regular inspection during maintenance is the best way to catch wear early.
How often should transom bellows be replaced?
As a preventative maintenance item, most manufacturers recommend replacing bellows every 3-5 years, depending on usage and whether the boat is in fresh or saltwater. The gimbal bearing should be inspected at the same time and replaced if it feels rough or noisy.
What is the difference between a greasable and sealed gimbal bearing?
A greasable bearing has a fitting that allows you to add grease periodically, which can extend its life if done correctly. A sealed bearing is pre-lubricated for its entire service life and requires no maintenance. This kit includes a high-quality sealed bearing for reliability and ease of use.
Is it normal to have a small amount of water in the bellows area?
No, the bellows are designed to create a watertight seal. Any water intrusion indicates a leak that must be addressed immediately to prevent catastrophic damage to the gimbal bearing, U-joints, and transom assembly.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). Built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, batch-inspected for consistency.
Shipping speed & cost
We ship worldwide quickly—typical transit 5–15 days. Standard shipping is free; expedited options appear at checkout where available.
Warranty & returns
Covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, contact support with your order details. Returns are accepted within our standard window (unused & in original condition). See our policy page or reach out for instructions.
Safety & Important Info
- Verify images/specifications vs your original part. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement, not an OEM component.
- Professional installation is recommended for safety and performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and tested for real-world conditions.
- Fast Global Fulfillment — Free standard delivery to most regions in 5–15 days.
- Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.
Payment & Security
Payment methods
Your payment information is processed securely. We do not store credit card details nor have access to your credit card information.
