U-Joint Bellows Installation Tool – Fits MerCruiser Alpha & Bravo Drives (Replaces 91-818162)
U-Joint Bellows Installation Tool – Fits MerCruiser Alpha & Bravo Drives (Replaces 91-818162) 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.
U-Joint Bellows Installation Tool – Fits MerCruiser Alpha & Bra...
U-Joint Bellows Installation Tool – Fits MerCruiser Alpha & Bravo Drives (Replaces 91-818162) is backordered and will ship as soon as it is back in stock.
Product Details
This U-Joint Bellows Installation Tool is used to install the aluminum expander ring into the U-joint bellows on MerCruiser sterndrives. It is specifically designed for Alpha One Generation II drives (1991 and newer), all Bravo models (I, II, III, X, XR, XZ from 1988 and newer), Blackhawk, and Vazer sterndrives.
This tool directly replaces Mercury/MerCruiser part number 91-818162, Sierra 18-9870, and Mallory 9-79821.
- Installs aluminum expander rings securely into U-joint bellows.
- Designed for use with a standard engine alignment tool or a similar driving rod.
- Constructed from durable materials for repeated use.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury/MerCruiser | 91-818162 |
| Sierra | 18-9870 |
| Mallory | 9-79821 / 79821 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This tool is designed for the following MerCruiser sterndrive models.
| Brand | Model | Years | OEM Part No. | Notes |
|---|---|---|---|---|
| MerCruiser | Alpha One Generation II | 1991 and newer | 91-818162 | For U-joint bellows installation |
| MerCruiser | Bravo I | 1988 and newer | 91-818162 | For U-joint bellows installation |
| MerCruiser | Bravo II | 1988 and newer | 91-818162 | For U-joint bellows installation |
| MerCruiser | Bravo III | 1988 and newer | 91-818162 | For U-joint bellows installation |
| MerCruiser | Bravo X | All years | 91-818162 | For U-joint bellows installation |
| MerCruiser | Bravo XR | All years | 91-818162 | For U-joint bellows installation |
| MerCruiser | Bravo XZ | All years | 91-818162 | For U-joint bellows installation |
| MerCruiser | Blackhawk | All years | 91-818162 | For U-joint bellows installation |
| MerCruiser | Vazer | All years | 91-818162 | For U-joint bellows installation |
Technical Specs
- Product Type
- U-Joint Bellows Installation Tool
- Function
- Installs aluminum expander rings into U-joint bellows
- Compatible Drives
- Alpha One Gen II, Bravo I/II/III, Blackhawk
- Material
- Varies by manufacturer (e.g., Aluminum, PVC Plastic)
- Package Dimensions
- 15 × 10 × 3 cm
- Weight
- 0.50 lbs (0.23 kg)
What’s in the Box
- 1 x U-Joint Bellows Installation Tool (Replaces 91-818162)
Installation Notes
- Apply a small amount of bellows adhesive to the bellows housing on the transom assembly.
- Place the aluminum bellows sealing ring into position on the edge of the bellows.
- Position the installation tool over the bellows to hold it in place.
- Use a driving rod (an engine alignment tool works well) through the center hole of the tool to hammer the aluminum ring into its final position.
- Once the ring is fully seated, remove the installation tool.
Troubleshooting & FAQ
What drives is this installation tool compatible with?
This tool is designed for the installation of U-joint bellows on MerCruiser Alpha One Generation II (1991 and newer), Bravo series (Bravo I, II, III, X, XR, XZ from 1988 and newer), Blackhawk, and Vazer sterndrives.
Do I need any other tools for this job?
Yes. This installation tool is used in conjunction with an engine alignment tool or a similar long driving rod. The rod passes through the center of this tool to apply force and seat the aluminum expander ring.
What is the difference between the OEM Mercury tool and this one?
Our aftermarket tool is built to meet or exceed original specifications for a precise fit and reliable function. The primary material may differ; OEM tools are typically aluminum, while some aftermarket versions may be made of high-strength PVC plastic, offering a durable and cost-effective alternative.
How do I know if I need to replace my U-joint bellows?
Inspect your bellows regularly for cracks, splits, or signs of water intrusion in the gimbal bearing area. Any damage requires immediate replacement. This tool is necessary for correctly installing the new bellows retainer ring during that job.
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.
