U-Joint Bellows Kit – Fits MerCruiser Alpha One Gen II (Replaces 816431A1)
U-Joint Bellows Kit – Fits MerCruiser Alpha One Gen II (Replaces 816431A1) is backordered and will ship as soon as it is back in stock.
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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.).
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Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
U-Joint Bellows Kit – Fits MerCruiser Alpha One Gen II (Replaces 81...
Product Details
This U-Joint Bellows Kit – Fits MerCruiser Alpha One Gen II is a crucial replacement part for MerCruiser Alpha One Gen II drives manufactured in 1991 and newer (serial number D469859 and up). It is engineered to protect the vital u-joint and driveshaft assembly from water intrusion and corrosion.
This kit serves as a direct cross-reference for Mercury 816431A1, Sierra 18-2747, and GLM 89180, ensuring a perfect match for your maintenance needs.
- Designed for direct OEM replacement to ensure proper fit and function.
- Features a robust worm gear clamp system for a secure, watertight seal.
- Includes all essential components for a complete bellows replacement.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury | 816431A1 |
| Sierra | 18-2747 |
| GLM | 89180 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
| Brand | Model | Years | OEM Part No. | Notes |
|---|---|---|---|---|
| MerCruiser | Alpha One Gen II | 1991 and newer | 816431A1 | For serial number D469859 and up |
Technical Specs
- Product Type
- U-Joint Bellows Kit
- Installation
- Direct OEM replacement
- Connection
- Worm gear clamp system
- Housing Material
- Rubber bellows with metal components
- Housing Color
- Black
- Dimensions
- 12.5" H x 14.0" W x 14.0" L
- Weight
- 27.2 g (0.96 oz)
- Fitting Type
- U-Joint assembly
- Other Technical Attributes
- For Alpha One Generation II 1991 and newer
What’s in the Box
- 1 x U-Joint Bellows Assembly (816431A1)
- 1 x Grounding Clip (54-86049)
- 1 x Worm Gear Clamp (54-815504372)
- 1 x Bellows Sleeve (816607)
Installation Notes
- Ensure the engine is off and the outdrive is trimmed up and safely supported.
- Carefully remove the old bellows, clamps, and grounding clip. Take note of the grounding clip's position.
- Thoroughly clean the mounting surfaces on the transom assembly and bell housing, removing any old sealant or debris.
- Inspect the U-joints and gimble bearing for signs of wear, rust, or water damage before proceeding.
- Slide the new bellows sleeve and bellows onto the bell housing.
- Install the new grounding clip in its correct position to prevent corrosion.
- Align the bellows correctly and secure it tightly with the provided worm gear clamps, ensuring a watertight seal.
- Double-check that the bellows is not twisted or pinched before lowering the drive.
Troubleshooting & FAQ
How do I know if my U-joint bellows needs replacing?
Visible signs of a failing bellows include cracks, splits, dry rot, or stiffness in the rubber. The most critical sign is finding water inside the bellows during an inspection, which can lead to catastrophic U-joint and gimbal bearing failure.
What is the recommended replacement interval for this part?
It is recommended to inspect your U-joint bellows annually. As a preventative measure, most marine mechanics suggest replacement every 3-5 years, depending on usage (saltwater vs. freshwater) and storage conditions.
Can I install this bellows kit myself?
While DIY installation is possible for experienced home mechanics with the right tools, professional installation is highly recommended. An improper seal can lead to major water damage to the drive components.
What is the function of the included grounding clip?
The grounding clip is a critical component that creates an electrical bond between drive parts. This helps prevent galvanic corrosion, which occurs when dissimilar metals are in contact in a marine environment.
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
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