Upper Gearcase Seal Kit – Fits MerCruiser Bravo I, II, III, X, XR, XZ & Blackhawk Stern Drives (Replaces 26-16709A1, 26-16709A2)
Upper Gearcase Seal Kit – Fits MerCruiser Bravo I, II, III, X, XR, XZ & Blackhawk Stern Drives (Replaces 26-16709A1, 26-16709A2) is backordered and will ship as soon as it is back in stock.
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Worry-free returns
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.).
You should expect to receive your refund within four weeks of giving your package to the return shipper, however, in many cases you will receive a refund more quickly. This time period includes the transit time for us to receive your return from the shipper (5 to 10 business days), the time it takes us to process your return once we receive it (3 to 5 business days), and the time it takes your bank to process our refund request (5 to 10 business days).
If you need to return an item, simply login to your account, view the order using the "Complete Orders" link under the My Account menu and click the Return Item(s) button. We'll notify you via e-mail of your refund once we've received and processed the returned item.
Delivery and Shipping
Delivery and Shipping
Free standard shipping on all orders under 1 KG
Upper Gearcase Seal Kit – Fits MerCruiser Bravo I, II, III, X, XR, ...
Product Details
This Upper Gearcase Seal Kit – Fits MerCruiser Bravo I, II, III, X, XR, XZ & Blackhawk Stern Drives provides all necessary seals and O-rings for a complete overhaul of the upper gearcase on MerCruiser Bravo series stern drives manufactured from 1988 and later. This includes Bravo I, II, and III models, as well as the Blackhawk variant (1994–1995).
It serves as a direct replacement for MerCruiser part numbers 26-16709A1 and 26-16709A2, and is an interchange for Sierra 18-2643, GLM 87480, and Mallory 9-74301.
- Engineered for installation to OEM specifications.
- Includes a comprehensive set of O-rings, seals, washers, and gaskets for the upper gearcase.
- Restores seal integrity to prevent water intrusion and oil leaks.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| MerCruiser | 26-16709A1 |
| MerCruiser | 26-16709A2 |
| Sierra | 18-2643 |
| GLM | 87480 |
| Mallory | 9-74301 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This kit is designed for MerCruiser Bravo series sterndrives.
| Brand | Model | Years | OEM Part No. |
|---|---|---|---|
| MerCruiser | Bravo I | 1988 and Up | 26-16709A1 / 26-16709A2 |
| MerCruiser | Bravo II | 1988 and Up | 26-16709A1 / 26-16709A2 |
| MerCruiser | Bravo III | 1988 and Up | 26-16709A1 / 26-16709A2 |
| MerCruiser | Blackhawk | 1994–1995 | 26-16709A1 / 26-16709A2 |
Technical Specs
- Product Type
- Upper Gearcase Seal Kit
- Installation
- OEM Specification
- Housing Material
- Various (O-rings, seals, washers)
- Compatible Systems
- Bravo I, II, III, X, XR, XZ, Blackhawk
- Application
- Upper Gearcase
What’s in the Box
- O-Rings
- Seals
- Washers
- Oil Seals
- Gear Housing Drain Screw Gaskets
- Keepers (#97351)
- Spring Kit
Installation Notes
- Disconnect the battery and ensure the engine is off and cool.
- Place the drive in the full-down position and drain the gear lube from the upper gearcase.
- Remove the upper sterndrive unit according to your service manual's procedures.
- Carefully disassemble the upper gearcase, laying out all parts in order on a clean surface.
- Systematically remove all old seals, O-rings, and gaskets, taking care not to scratch any metal surfaces.
- Thoroughly clean all sealing surfaces before installing the new components.
- Lubricate the new seals and O-rings with a light coat of 2-4-C marine grease or an appropriate lubricant.
- Install the new components from the kit, ensuring each seats correctly without being pinched or twisted.
- Reassemble the upper gearcase, torquing all fasteners to the manufacturer's specified values.
- Reinstall the sterndrive unit, refill with fresh high-performance gear lube, and check for leaks before operating.
Troubleshooting & FAQ
Will this kit fit my specific Bravo XR drive?
Yes, this kit is designed for the entire Bravo series, including Bravo I, II, III, X, XR, and XZ models from 1988 and up. Always cross-reference your OEM part number (26-16709A1 or 26-16709A2) to ensure perfect fitment.
What are the signs of a failing upper gearcase seal?
The most common indicators are milky or water-contaminated gear lube, a visible oil sheen on the water around your drive, or a persistent low gear lube level. Any of these symptoms warrant an inspection and likely a seal replacement.
How difficult is the installation?
This task is considered intermediate to advanced. It requires specific tools, including a torque wrench, and a good understanding of sterndrive mechanics. We recommend referencing a MerCruiser service manual for your specific model and professional installation if you are not experienced.
How do these seals compare to the original MerCruiser parts?
Our aftermarket seals are manufactured to meet or exceed OEM specifications for material durability, fit, and function. They provide a reliable seal to protect your gearcase from water intrusion and oil loss under normal marine operating conditions.
How often should these seals be replaced?
There is no fixed replacement interval. Seals should be inspected for leaks during regular maintenance (e.g., at the end of each season when changing gear lube) and replaced whenever the gearcase is disassembled for service or if any signs of failure appear.
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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