U-Joint Bellows – Fits MerCruiser Bravo & Blackhawk Stern Drives (Replaces 86840A05, 86840A3, 8M0062406)
U-Joint Bellows – Fits MerCruiser Bravo & Blackhawk Stern Drives (Replaces 86840A05, 86840A3, 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 Stern Drive...
Product Details
This U-Joint Bellows is designed for MerCruiser Bravo I, II, III (all variants) and Blackhawk stern drives manufactured between 1988 and 2009. It serves as a crucial component for protecting the universal joint from marine elements, ensuring drivetrain longevity and performance.
It is a direct replacement for MerCruiser/Mercury part numbers 86840A05, 86840A3, and 8M0062406, as well as Sierra 18-2756 and OMC/Johnson/Evinrude 0775490.
- Engineered for direct replacement and easy installation.
- Constructed from durable, marine-grade rubber to resist saltwater and UV damage.
- Kit typically includes essential hardware like an aluminum ring and stainless steel clamp.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket brands.
| Brand | Part Number |
|---|---|
| MerCruiser / Mercury | 86840A05, 86840A3, 8M0062406 |
| Sierra | 18-2756 |
| OMC / Johnson / Evinrude | 0775490 |
Engine & Model Compatibility
Confirm your engine model and year in the table below.
For MerCruiser/Mercury, this bellows fits Bravo and Blackhawk models as specified.
| Brand | Model | Years | OEM Part No. |
|---|---|---|---|
| MerCruiser | Bravo One | 1988–1998 | 86840A05, 86840A3, 8M0062406 |
| MerCruiser | Bravo Two | 1988–1998 | 86840A05, 86840A3, 8M0062406 |
| MerCruiser | Bravo Three | 1988–1998 | 86840A05, 86840A3, 8M0062406 |
| MerCruiser | Bravo XR/XZ | 1998–2009 | 86840A05, 86840A3, 8M0062406 |
| MerCruiser | Integrated Transom | 1998–2009 | 86840A05, 86840A3, 8M0062406 |
| MerCruiser | Blackhawk | 1994–1995 | 86840A05, 86840A3, 8M0062406 |
Technical Specs
- Product Type
- U-Joint Bellows
- Installation
- Direct replacement
- Housing Material
- Marine-grade rubber
- Product Dimensions
- 16.5" L x 15.5" W x 15.5" H
- Warranty
- 1 Year (varies by brand)
- Other Technical Attributes
- Includes aluminum ring and stainless steel clamp (varies by brand)
What’s in the Box
- 1 x Bellows
- 1 x Aluminum Ring
- 1 x Stainless Clamp
Installation Notes
- Trim the stern drive to the full up/trailer position and disconnect the battery.
- Remove the stern drive assembly from the bell housing according to the manufacturer's service manual.
- Carefully cut and remove the old clamps and the damaged u-joint bellows.
- Clean the mounting surfaces on the bell housing and stern drive thoroughly.
- Install the new aluminum ring and bellows, ensuring a snug fit.
- Secure the new bellows with the provided stainless steel clamps, tightening them to the specified torque.
- Inspect the installation for proper sealing and alignment.
- Reinstall the stern drive assembly, reconnect the battery, and test for leaks.
Troubleshooting & FAQ
How do I know if my U-joint bellows is failing?
Common signs include visible cracks or splits in the rubber, water inside the bellows (which can lead to catastrophic u-joint failure), or a grinding noise from the transom area during operation.
Can I install this part myself?
While DIY installation is possible for experienced mechanics, it requires removing the stern drive. We recommend professional installation to ensure proper sealing and prevent damage to the drivetrain.
How often should a U-joint bellows be replaced?
It is recommended to inspect bellows annually and replace them every 3–5 years, or immediately if any signs of wear, cracking, or damage are found. This is a critical preventative maintenance item.
Will this fit a Bravo X drive?
Yes, this bellows is listed as compatible with Bravo XR and XZ models from 1998 to 2009. Always double-check your specific OEM part number against our Part Number Matrix.
Is this part the same as the exhaust bellows?
No. This is the U-joint (drive shaft) bellows, which protects the drivetrain. The exhaust bellows is a separate part that carries exhaust gases. Ensure you are ordering the correct bellows for your needs.
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).
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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