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

This complete aftermarket seal kit contains the necessary components to reseal the upper gearcase on MerCruiser Bravo stern drives. It is designed for Bravo I, II, and III models from 1988 and up, as well as Bravo X, XR, XZ, and the Blackhawk variant (1994-1995).

This kit is a direct replacement for MerCruiser part numbers 26-16709A1 and 26-16709A2, as well as aftermarket parts from Sierra, GLM, and Mallory.

• Engineered to meet OEM specifications for a reliable fit and performance.
• Comprehensive kit includes O-Rings, Seals, Washers, and Gaskets for a complete service.
• Broad compatibility across the most popular MerCruiser Bravo stern drive models.

Part Number Cross-Reference

Use this table to confirm equivalent part numbers across OEM and aftermarket brands.

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.

Technical Specifications

Package Contents

• O-Rings
• Seals
• Washers
• Oil Seals
• Gear Housing Drain Screw Gaskets
• Keepers (#97351)
• Spring Kit

Installation Guide

1. Ensure the engine is off and the drive is in a safe, stable position for service. Drain the gear lube from the upper gearcase completely.
2. Carefully disassemble the upper gearcase components. Keep all parts organized and note their orientation.
3. Remove all old seals, O-rings, and gaskets. Take care not to scratch or damage any of the sealing surfaces during removal.
4. Thoroughly clean all mating surfaces to remove old sealant, corrosion, and debris.
5. Install the new seals and O-rings from the kit. Lightly lubricate them with 2-4-C marine grease or high-quality gear oil as specified by the service manual.
6. Ensure correct orientation and seating depth for all new oil seals.
7. Reassemble the gearcase. Torque all bolts and fasteners to the manufacturer's recommended specifications.
8. Refill the gearcase with fresh, high-performance marine gear lube.
9. Once filled, pressure test the gearcase according to the service manual to confirm there are no leaks before operation.

Troubleshooting & FAQ

Q: How do I confirm this kit fits my Bravo stern drive?

A: This kit is designed for MerCruiser Bravo I, II, and III models from 1988 and up, as well as Bravo X, XR, XZ, and Blackhawk (1994-1995) models. To guarantee fitment, please cross-reference your original part number with those listed: MerCruiser 26-16709A1, 26-16709A2; Sierra 18-2643; GLM 87480; or Mallory 9-74301.

Q: What are the signs that my upper gearcase seals are failing?

A: The most common signs of a failed gearcase seal include observing oil leaks around the upper drive unit, or discovering water has mixed with the gear lube, which gives it a milky or creamy appearance. Prompt replacement is crucial to prevent severe gear damage.

Q: Does this kit include every single seal I might need?

A: This is a comprehensive upper gearcase seal kit that contains all the primary seals, O-rings, gaskets, and washers required for that specific application. We strongly recommend reviewing the 'Package Contents' list and Explosion Diagram to confirm it matches all the components needed for your repair.

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?

• Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
• Fast Global Shipping: Free delivery worldwide in 5–15 days.
• Direct from Manufacturer: Competitive pricing without compromising quality.