Driveshaft Housing Seal Kit – Fits MerCruiser Bravo I, II, III, X, XR, XZ (Replaces 26-16709A2)
Driveshaft Housing Seal Kit – Fits MerCruiser Bravo I, II, III, X, XR, XZ (Replaces 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
Product Details
This is a complete Driveshaft Housing Seal Kit for MerCruiser Bravo I, II, III, X, XR, and XZ stern drives manufactured from 1988 and later (serial number 0B664190 and up). It is also compatible with MerCruiser Blackhawk stern drives from 1994-1995 (serial number 0F186717 and up). This kit contains all necessary seals and gaskets for servicing the upper driveshaft housing.
It serves as a direct replacement for Mercury/MerCruiser part numbers 26-16709A2 and 26-16709A1, as well as aftermarket equivalents from Sierra (18-2643) and GLM (87480).
- For installation in the upper unit/gearcase of compatible stern drives.
- Engineered to meet or exceed OEM specifications for a reliable seal.
- Comes with a 1-year factory warranty against defects and workmanship.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury/MerCruiser | 26-16709A2 |
| Mercury/MerCruiser | 26-16709A1 |
| Sierra | 18-2643 |
| GLM | 87480 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
For MerCruiser models, ensure your serial number falls within the specified range for proper fitment. This kit is designed for Bravo and Blackhawk series drives.
| Brand | Model | Years | OEM Part No. | Notes |
|---|---|---|---|---|
| MerCruiser | Bravo I | 1988–Present | 26-16709A2 | Serial Range: 0B664190 & Up |
| MerCruiser | Bravo II | 1988–Present | 26-16709A2 | Serial Range: 0B664190 & Up |
| MerCruiser | Bravo III | 1988–Present | 26-16709A2 | Serial Range: 0B664190 & Up |
| MerCruiser | Bravo X | 26-16709A2 | ||
| MerCruiser | Bravo XR | 26-16709A2 | ||
| MerCruiser | Bravo XZ | 26-16709A2 | ||
| MerCruiser | Blackhawk | 1994–1995 | 26-16709A2 | Serial Range: 0F186717 & Up |
Technical Specs
- Product Type
- Driveshaft Housing Seal Kit
- Installation Location
- Upper Unit/Gearcase
- Dimensions
- 13.5 in x 3.0 in x 10.5 in
- Weight
- 0.19 lbs (0.09 kg)
- Compatible Drives
- MerCruiser Bravo I, II, III, X, XR, XZ, and Blackhawk
- Warranty
- 1 year factory warranty against defects and workmanship
What’s in the Box
The complete kit (equivalent to 26-16709A2) includes the following components:
- 2 x Keeper (12920)
- 1 x Spring Kit (12930)
- 2 x Gasket (31170)
- 1 x O-ring (81030)
- 2 x O-ring (80180)
- 2 x O-ring (81180)
- 1 x O-ring (81270)
- 1 x O-ring (81570)
- 1 x O-ring (82150)
- 1 x O-ring (82380)
- 1 x O-ring (82390)
- 1 x O-ring (82530)
- 1 x O-ring (83465)
- 1 x Seal (85820)
- 1 x Seal (86310)
- 1 x Seal (86720)
- 1 x Oil Seal (86730)
Installation Notes
- Disconnect the boat's battery for safety.
- Place a suitable container under the stern drive and drain the gearcase oil completely.
- Remove the upper gearcase unit from the lower unit according to your service manual's procedure.
- Carefully disassemble the driveshaft housing, noting the orientation of all components.
- Remove all old seals, o-rings, and gaskets from the housing.
- Thoroughly clean all mating surfaces, ensuring they are free of old gasket material, sealant, and corrosion.
- Carefully install the new seals and o-rings from the kit, lightly lubricating them with 2-4-C marine grease or gear oil.
- Reassemble the driveshaft housing, torquing fasteners to the manufacturer's specified values.
- Reinstall the upper gearcase onto the lower unit.
- Refill the stern drive with the correct type and amount of high-performance gear lube.
- Once assembled, check for any leaks around the sealed areas before operating the vessel.
Troubleshooting & FAQ
How do I know if my driveshaft housing seals are failing?
Common signs of failing seals include water intrusion into the gear lube (visible as milky or creamy oil when drained) or oil leaking externally from the upper drive unit. A pressure and vacuum test is the definitive way to confirm a leak.
Will this kit fit a Bravo drive outside the specified serial number range?
No. This kit is specifically for MerCruiser Bravo drives with serial number 0B664190 and up, and Blackhawk drives with serial number 0F186717 and up. Using it on earlier models may result in improper fitment and leaks. Always verify your serial number before ordering.
What is the recommended replacement interval for these seals?
It is recommended to inspect your gear lube annually for water intrusion. Seals should be replaced whenever the drive unit is disassembled for other service or immediately if a leak is detected. Proactive replacement every 3-5 years or 300-500 hours is good preventive maintenance.
Is any special sealant required during installation?
Generally, no additional sealant is needed for the o-rings and rubber seals. Gaskets may require a light application of a suitable gasket dressing or sealant as specified in your official service manual. Always refer to your manual for the correct procedure.
OEM vs. Aftermarket?
This listing is an aftermarket replacement (not OEM). It is built to OEM-level specifications with comparable materials. Manufactured in an ISO 9002 facility, it is batch-inspected for consistency and reliability.
Shipping speed & cost?
We ship worldwide quickly—typical transit is 5–15 days. Standard shipping is free; expedited options will appear at checkout where available for your location.
Warranty & returns?
This product is covered by a 1-year warranty against manufacturing defects under normal use. If issues arise, please contact our support team with your order details. Returns are accepted within our standard window, provided the item is unused and in its original condition. See our policy page or reach out for instructions.
Safety & Important Info
- Verify images and specifications against your original part before purchase. If anything differs—even if your model appears compatible—do not purchase.
- This is an aftermarket replacement part, not an OEM component.
- Professional installation is highly recommended for safety and optimal performance.
About Sea Sierra
- Pro-Grade Standards — We supply marine parts engineered to OEM-level tolerances and rigorously tested for real-world conditions.
- Fast Global Fulfillment — We offer free standard delivery to most regions, with typical transit times of 5–15 days.
- Manufacturer-Direct Value — Our parts provide fair pricing without compromising on materials or quality control.
Payment & Security
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