U-Joint Bellows – Fits MerCruiser Bravo & Blackhawk Drives (Replaces 86840A05, 8M0062406)
U-Joint Bellows – Fits MerCruiser Bravo & Blackhawk Drives (Replaces 86840A05, 8M0062406) 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
U-Joint Bellows – Fits MerCruiser Bravo & Blackhawk Drives (Rep...
Product Details
This aftermarket MerCruiser Bravo U-Joint Bellows is designed to protect the U-joint and driveshaft assembly on MerCruiser Bravo and Blackhawk sterndrives. It fits Bravo I, Bravo II, Bravo III, and Blackhawk models from 1988 and newer, creating a crucial seal as the drive shaft passes through the transom.
It serves as a direct cross-reference for multiple OEM and aftermarket part numbers, including Sierra 18-2756, GLM 89140, Mallory Marine 9-72702, and Mercury 86840A05 / 8M0062406.
- Designed for direct, hassle-free installation.
- Constructed from durable neoprene rubber to resist oil, saltwater, and abrasion.
- Includes the necessary stainless steel hose clamps for a secure fit.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury | 86840A05 |
| Mercury | 8M0062406 |
| Sierra | 18-2756 |
| GLM | 89140 |
| Mallory Marine | 9-72702 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This part is designed exclusively for the MerCruiser sterndrive models listed below.
| Brand | Model | Years | OEM Part No. | Notes |
|---|---|---|---|---|
| MerCruiser | Bravo I | 1988–Present | 86840A05/8M0062406 | |
| MerCruiser | Bravo II | 1988–Present | 86840A05/8M0062406 | |
| MerCruiser | Bravo III | 1988–Present | 86840A05/8M0062406 | |
| MerCruiser | Blackhawk | 1988–Present | 86840A05/8M0062406 |
Technical Specs
- Product Type
- U-Joint Bellows
- Material
- Neoprene rubber
- Color
- Black
- Design
- Ridge design for improved sealing
- Application
- Seals drive shaft as it passes through the transom
- Box Dimensions
- 15cm x 15.5cm x 16cm
- Warranty
- Manufacturer warranty
What’s in the Box
- 1 x U-Joint Bellows (Replaces 86840A05/8M0062406)
- 1 x Stainless Steel Hose Clamp
Installation Notes
- Disconnect the vessel's battery for safety.
- Tilt the sterndrive to the full "up" or "trailer" position to access the bellows.
- Carefully remove the old hose clamps and cut away the old, damaged bellows.
- Thoroughly clean the mounting surfaces on the bell housing and transom assembly.
- Fit the new U-joint bellows into position, ensuring it is seated correctly on both ends.
- Secure the new bellows with the provided stainless steel hose clamps. Tighten firmly but do not overtighten.
- Lower the sterndrive and inspect the new installation for proper alignment and sealing.
- Reconnect the battery and test the sterndrive's function in the water, checking for any leaks.
Troubleshooting & FAQ
How do I know if my U-joint bellows needs replacing?
Inspect the bellows regularly for cracks, splits, or brittleness. Any sign of water inside the bellows or grease leaking out indicates an immediate need for replacement to prevent catastrophic U-joint failure.
What happens if a U-joint bellows fails?
A failed bellows will allow water to enter the sterndrive, quickly destroying the U-joints and gimbal bearing. This can lead to a complete loss of propulsion and costly repairs.
What is the recommended replacement interval?
As a preventative maintenance item, it's wise to inspect your bellows annually and replace it every 3–5 years, or immediately if any damage is found, regardless of age.
Is this bellows compatible with all Bravo drives?
It's designed for a wide range of MerCruiser Bravo and Blackhawk drives, typically from 1988 onward. Due to manufacturing variations, always double-check that your drive model and year fall within this range and visually compare the old part to our photos.
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, typically arriving in 5–15 days.
- Manufacturer-Direct Value: Fair pricing on quality components without the retail markup.
Payment & Security
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