Transom Seal Service Bellows Kit – Fits MerCruiser R, MR Alpha One Gen 1, Alpha One SS (Replaces MerCruiser 30-803097T1, Sierra 18-8213)
Transom Seal Service Bellows Kit – Fits MerCruiser R, MR Alpha One Gen 1, Alpha One SS (Replaces MerCruiser 30-803097T1, Sierra 18-8213) is backordered and will ship as soon as it is back in stock.
Worry-free returns
Worry-free returns
Shop with confidence. If you’re not completely satisfied, eligible items may be returned within the return window, provided they are unused and in original packaging.
If the return is due to our error or a defective item, we’ll make it right.
Please contact us before returning any item.
Delivery and Shipping
Delivery and Shipping
Orders are typically processed within 1–2 business days.
U.S. orders usually arrive within 6–15 days, depending on stock location and destination.
International delivery times may vary due to customs processing.
Tracking information will be provided once your order ships.
Transom Seal Service Bellows Kit – Fits MerCruiser R, MR Alpha One ...
Transom Seal Service Bellows Kit – Fits MerCruiser R, MR Alpha One Gen 1, Alpha One SS (Replaces MerCruiser 30-803097T1, Sierra 18-8213) is backordered and will ship as soon as it is back in stock.
Product Details
This Transom Seal Service Bellows Kit – Fits MerCruiser Alpha One Gen 1, R, MR is a comprehensive aftermarket solution for MerCruiser R, MR, and Alpha One Gen 1 sterndrives (1983–1991) with serial numbers 6225577 and up. It also fits Alpha One SS models from 1986–1989 with serial numbers 0A545004 and up.
It serves as a direct replacement for MerCruiser part 30-803097T1, Sierra 18-8213 / 18-2601-1, and Mallory 9-72902, providing all necessary components for a complete transom service.
- Engineered as a direct replacement for a precise fit.
- Includes all required gaskets, o-rings, and hose clamps for installation.
- Bellows are constructed from durable neoprene rubber to withstand the marine environment.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| MerCruiser | 803097T1 / 30-803097T1 |
| Sierra | 18-8213 / 18-2601-1 |
| Mallory | 9-72902 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For MerCruiser owners, it is critical to verify your model and serial number range to ensure correct fitment. This kit is specific to the models listed.
| Brand | Model | Rated HP | Stroke | Years | OEM Part No. | Notes |
|---|---|---|---|---|---|---|
| MerCruiser | R, MR Alpha One | Various | 4-Stroke | 1983–1991 | 30-803097T1 | Serial range: 6225577 & up |
| MerCruiser | Alpha One SS | Various | 4-Stroke | 1986–1989 | 30-803097T1 | Serial range: 0A545004 & up |
Technical Specs
- Product Type
- Transom Seal Service Bellows Kit
- Installation
- Direct replacement
- Connection
- Hose clamps (included)
- Housing Material
- Neoprene rubber bellows
- Weight
- 2.23 kg (4.91 lb)
- Other Technical Attributes
- Complete kit with all necessary components
What’s in the Box
- 1 x U-Joint Bellows (60932A4)
- 1 x Exhaust Bellows (18654A1)
- 1 x Shift Cable Bellows (74639)
- 1 x Gimbal Bearing (30-60792A4)
- 1 x Water Hose 3/4" (32-41725-33)
- 1 x Water Hose 5/8" (32-32461)
- 1 x Gasket Kit (27-94996T2)
- 4 x O-Rings (various sizes)
- 1 x Bell Housing Gasket
- 1 x O-Ring (25-33504)
- 1 x O-Ring (25-35027)
- 2 x O-Rings (25-25439)
- Mounting hardware and hose clamps
Installation Notes
- Disconnect the battery and remove the sterndrive unit from the transom assembly.
- Carefully remove the old U-joint, exhaust, and shift cable bellows. Inspect and remove the old gimbal bearing.
- Thoroughly clean all mating surfaces on the bell housing and transom assembly, removing any old gasket material or sealant.
- Press the new gimbal bearing into the housing, ensuring it is properly aligned and seated.
- Install the new shift cable, exhaust, and U-joint bellows, using a bellows expander tool for the U-joint bellows.
- Secure all bellows with the provided hose clamps, ensuring they are tight and properly positioned.
- Replace the water intake hoses and install the new bell housing gasket and o-rings.
- Reinstall the sterndrive, using an alignment tool to ensure proper engine-to-drive alignment.
- Once assembled, lower the drive into the water and check thoroughly for any leaks before starting the engine.
Troubleshooting & FAQ
How do I know if this kit fits my sterndrive?
Check your model (R, MR, Alpha One Gen 1, or Alpha One SS) and year. Crucially, verify your serial number is within the range: 6225577 and up for Alpha One Gen 1 (1983–1991) or 0A545004 and up for Alpha One SS (1986–1989).
What are the signs my transom seal kit is failing?
Common signs include water entering the boat's bilge area, a grinding or clicking noise from the gimbal bearing when turning the wheel, or visible cracks, splits, or perishing on the rubber bellows.
How often should the transom bellows be replaced?
As a preventative maintenance item, it is best practice to inspect bellows annually and replace them every 3–5 years, depending on usage and water conditions (saltwater vs. freshwater). Replace them immediately if you see any signs of wear or damage.
Is the included gimbal bearing pre-greased?
No, the gimbal bearing supplied in this kit is not pre-greased. It is critical to grease the bearing properly upon installation using a quality marine grease to prevent premature failure.
Are special tools required for this installation?
Yes, replacing a transom seal kit typically requires specialized marine tools, including a gimbal bearing puller/installer, a bellows expansion tool, and an engine alignment tool to ensure the drive is reinstalled correctly.
What is the difference between this kit and an OEM one?
This is an aftermarket kit designed to meet or exceed original manufacturer specifications using comparable, high-quality materials. It provides a reliable, cost-effective alternative to genuine OEM parts.
What is your policy on shipping speed & cost?
We ship worldwide quickly—typical transit is 5–15 days. Standard shipping is free for most orders, with expedited options available at checkout where applicable.
What warranty and return options do you offer?
This product is covered by a 1-year warranty against manufacturing defects under normal use. If you encounter an issue, please contact our support team with your order details. Returns are accepted within our standard window for unused items in their original condition.
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.
