Bellow Ring Installation Tool – Fits Mercury MerCruiser Alpha 1 Gen 2, Bravo, Blackhawk (Replaces 91-818162)
This specialty tool is designed for the precise installation of the aluminum bellow retainer ring on Mercury MerCruiser stern drives, including the Alpha One Gen 2, Bravo series, Blackhawk, and Vazer models. It ensures the retainer ring is seated correctly within the U-joint bellows without damage.
This tool is a direct replacement for Mercury MerCruiser part number 91-818162 and aftermarket equivalents like Sierra 18-9870. It is an essential tool for any sterndrive bellows service.
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Required for Installation: Must be used with an Engine Alignment Tool to ensure correct installation.
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Installation Method: Manual tool requires light, even taps from a hammer to seat the ring.
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Material: Made from high-strength PVC plastic to prevent marring or damaging components.
Part Number Cross-Reference
Use this table to confirm equivalent part numbers across OEM and aftermarket brands.
Brand |
Part Number |
Mercury MerCruiser |
91-818162 |
Sierra |
18-9870 |
MBSMFG |
BRSIT-D23 |
Compatible Engine Models
Confirm your engine model/year in the table below. For Mercury owners, here’s a guide to help you identify your engine’s serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.
Brand |
Model |
Rated HP |
Stroke |
OEM Part No. |
Notes |
Mercury MerCruiser |
Alpha One Gen 2 |
Various |
4-Stroke |
91-818162 |
U-Joint bellows installation |
Mercury MerCruiser |
Bravo |
Various |
4-Stroke |
91-818162 |
U-Joint bellows installation |
Mercury MerCruiser |
Blackhawk |
Various |
4-Stroke |
91-818162 |
U-Joint bellows installation |
Mercury MerCruiser |
Vazer |
Various |
4-Stroke |
91-818162 |
Per MercruiserParts.com source |
Technical Specifications
Specification |
Value |
Product Type |
Installation Tool |
Installation |
Manual; requires light hammer taps |
Housing Material |
PVC Plastic (aftermarket) or Aluminum (OEM/aftermarket options) |
Housing Color |
Black or Silver (depending on material) |
Other Technical Attributes |
Used with Engine Alignment Tool to properly install aluminum ring into U-joint bellows |
Package Contents
- 1 x Bellow Retainer Ring Installation Tool (91-818162)
Installation Guide
- Ensure the sterndrive is properly supported and prepared for bellows service according to the manufacturer's manual.
- Apply a light coat of a suitable lubricant, such as 2-4-C grease or bellows adhesive, to the aluminum retainer ring and the groove inside the U-joint bellows.
- Insert the clean retainer ring into the new bellows.
- Slide the Engine Alignment Tool through the gimbal housing and bellows to ensure everything is properly aligned.
- Place the Bellow Retainer Ring Installation Tool onto the aligned aluminum ring.
- Using a light hammer, gently tap the installation tool in a circular pattern to slowly and evenly press the ring into its seated position.
- Continue tapping until the tool bottoms out against the gimbal housing, which indicates the ring is fully installed in its groove.
- Remove the installation tool and the alignment bar.
- Visually inspect the retainer ring to confirm it is seated uniformly and securely.
Troubleshooting & FAQ
Q: How do I use this tool correctly?
A: This tool is designed to be used with an Engine Alignment Tool. After lubricating the ring and bellows, place the installation tool onto the ring and gently tap it with a hammer, moving in a circle, until the ring is fully seated in the bellows groove.
Q: Will this fit my Alpha One Gen 1 drive?
A: No, this tool is specifically for Alpha One Gen 2, Bravo, Blackhawk, and Vazer stern drives. It is not compatible with Gen 1 models, which use a different bellows design.
Q: What is the difference between this PVC tool and an aluminum OEM one?
A: OEM tools are traditionally made from aluminum. Our aftermarket tool is made from high-impact PVC plastic, which is highly durable, prevents scratching or marring the drive housing, and offers a more cost-effective solution for the same task.
Q: OEM vs. Aftermarket?
A: This listing is an aftermarket replacement part (not an OEM component). We build to OEM specifications using comparable-grade materials. Production is done in an ISO9002-certified facility, and each batch is inspected for consistent performance.
Q: How fast do you ship and how much does it cost?
A: We offer fast global shipping—typically 5–15 days worldwide—and standard shipping is free. Expedited options are available at checkout depending on your location.
Q: What is your warranty and return policy?
A: This product includes a 1-year warranty against manufacturing defects under normal use. If something goes wrong, contact our support team with your order details. Returns are accepted within our standard return window (unused & in original condition); please see our policy page or reach out for instructions.
Important Notes
- Verify that the product images and specifications match your original part. If discrepancies exist—even if your model is listed—do not proceed with the purchase.
- This product is an aftermarket replacement part and is not an OEM component.
- Professional installation is recommended to ensure safety and optimal performance.
Why Choose JLM MARINE?
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Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
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Fast Global Shipping: Free delivery worldwide in 5–15 days.
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Direct from Manufacturer: Competitive pricing without compromising quality.