MerCruiser Alpha One Gen II U-Joint Assembly – Fits Alpha One Gen II & Vazer (864281A2)
MerCruiser Alpha One Gen II U-Joint Assembly – Fits Alpha One Gen II & Vazer (864281A2) is backordered and will ship as soon as it is back in stock.
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Delivery and Shipping
Delivery and Shipping
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MerCruiser Alpha One Gen II U-Joint Assembly – Fits Alpha One Gen II & Vazer (864281A2) is backordered and will ship as soon as it is back in stock.
Product Details
This is a direct-replacement MerCruiser Alpha One Gen II U-Joint Assembly, engineered to fit MerCruiser sterndrive applications including Alpha One Gen II models from 1998 and newer (serial number 0L100040 and above) and all Vazer drives.
It serves as a direct interchange for Mercury part numbers 864281A2, 864281A01, 59830A5, 814819A2, 814819A7, and 865491A01.
- Designed for direct, hassle-free installation.
- Constructed from durable steel to withstand marine environments.
- Includes one complete U-Joint assembly as shown.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury | 864281A2 |
| Mercury | 864281A01 |
| Mercury | 865491A01 |
| Mercury | 814819A7 |
| Mercury | 814819A2 |
| Mercury | 59830A5 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
| Brand | Model | Years | OEM Part No. |
|---|---|---|---|
| MerCruiser | Alpha One Gen II | 1998–Newer (S/N 0L100040 and above) | 864281A2 |
| MerCruiser | Vazer | All | 864281A2 |
Technical Specs
- Product Type
- Universal Joint Assembly
- Installation
- Direct replacement
- Housing Material
- Steel
- Dimensions
- 62.0 cm × 23.0 cm × 15.0 cm
- Weight
- 5.85 kg (12.90 lb)
- Warranty
- Manufacturer warranty
- OEM Part Number
- 864281A2
- UPC/GTIN
- 0745061552418
What’s in the Box
- 1 x U-Joint Assembly (864281A2)
Installation Notes
- Disconnect the boat's battery before starting work.
- Safely position the sterndrive in the full tilt position and drain the gear lube.
- Remove the sterndrive from the gimbal housing.
- Separate the upper and lower units to access the U-joint shaft assembly.
- Carefully remove the old U-joint assembly, inspecting the gimbal bearing and bellows for wear or damage.
- Clean the input yoke splines and surrounding housing.
- Install the new U-joint assembly, ensuring it is properly seated in the yokes.
- Reassemble the drive components using new gaskets and seals as recommended by the service manual.
- Mount the sterndrive back onto the gimbal housing.
- Refill the drive with the correct type and amount of sterndrive gear lube.
- Reconnect the battery and test operation in a safe environment.
Troubleshooting & FAQ
How do I know if this U-joint assembly fits my engine?
This assembly is specifically for MerCruiser Alpha One Gen II sterndrives (1998 and newer, S/N 0L100040 and up) and Vazer drives. The most reliable method is to match your existing OEM part number to one of the cross-references listed in our Part Number Matrix.
What are the signs of a failing sterndrive U-joint?
Common symptoms include a clunking, grinding, or clicking noise when turning or shifting, excessive vibration that is felt through the boat, or visible rust and scoring around the U-joint caps. A torn U-joint bellow can also lead to premature failure due to water intrusion.
How often should the U-joints be serviced?
Follow the maintenance schedule in your MerCruiser service manual. Generally, U-joints should be inspected annually for signs of wear, rust, or lack of lubrication. The surrounding bellows should also be checked for cracks or leaks at the same time.
Can I replace just the bearing cross instead of the whole shaft?
While U-joint crosses can sometimes be replaced individually, it requires special tools to press them in and out without damaging the yokes. Replacing the entire assembly is often safer and more reliable, as it ensures all components are new, balanced, and free from fatigue.
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.
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