U-Joint Shift Bellows Kit – Fits OMC Cobra (1986 & Later) and Volvo Penta SX/DP Models (Replaces 3854270, 3858631)
This U-Joint Shift Bellows Kit provides a reliable replacement for specific OMC Cobra and Volvo Penta sterndrive models. It is engineered to protect the crucial U-joint and shift cable components from water intrusion and damage, ensuring smooth and safe operation.
This kit is a direct replacement for OMC Stern Drive part numbers 3854270 and 3858631, and Volvo Penta part numbers 3854270 and 3858631.
- Designed as a direct replacement for hassle-free installation.
- Manufactured from high-grade rubber/neoprene to meet or exceed OEM specifications.
- Includes one U-Joint Bellows and a corresponding clamp.
Part Number Cross-Reference
Use this table to confirm equivalent part numbers across OEM and aftermarket brands.
Brand |
Part Number |
OMC Stern Drive |
3854270/3858631 |
Volvo Penta |
3854270/3858631 |
GLM |
21962 |
Sierra |
18-2771 |
Mallory |
9-72930 |
Compatible Engine Models
Confirm your engine model/year in the table below.
OMC
Brand |
Model |
Years |
OEM Part No. |
Notes |
OMC |
Cobra |
1986 & Later |
3854270/3858631 |
Without cone clutch |
Volvo Penta
Brand |
Model |
OEM Part No. |
Volvo Penta |
SX-S |
3854270/3858631 |
Volvo Penta |
SX-C |
3854270/3858631 |
Volvo Penta |
SX-R |
3854270/3858631 |
Volvo Penta |
SX-M |
3854270/3858631 |
Volvo Penta |
DP-S |
3854270/3858631 |
Volvo Penta |
DP-S1 |
3854270/3858631 |
Volvo Penta |
DP-SM |
3854270/3858631 |
Technical Specifications
Specification |
Value |
Product Type |
U-Joint Shift Bellows Kit |
Installation |
Direct replacement |
Connection |
OEM-matching fittings |
Housing Material |
Rubber/neoprene |
Housing Color |
Black |
Fitting Type |
OEM-compatible fittings with clamps |
Warranty |
1 year manufacturer's warranty |
Other Technical Attributes |
Manufactured to OEM specifications using the exact same material as the originals. Produced in an ISO9002 certified factory. |
Package Contents
- 1 x U-Joint Bellows with Clamp (Replaces 3854270/3858631)
Installation Guide
- Ensure the engine is off and the sterndrive is trimmed to the full "up" position for access. Disconnect the negative battery terminal for safety.
- Carefully remove the old bellows and any clamp remnants. Inspect the drive and transom housing for cracks or damage.
- Thoroughly clean the mounting surfaces on both the transom and drive unit to ensure a clean, debris-free seal.
- Position the new U-Joint bellows, ensuring it is correctly seated and aligned on both ends without any twists.
- Secure the bellows using the provided clamp. Tighten the clamp to the manufacturer's recommended torque specification.
- After securing, double-check the seal around the entire bellows to confirm it is seated properly and will prevent water leaks.
- Reconnect the battery terminal, lower the drive, and test the installation by running the engine in the water and checking for any signs of water intrusion.
Troubleshooting & FAQ
Q: How can I confirm this bellows kit fits my specific sterndrive?
A: This kit is designed for OMC Cobra models from 1986 and later (without a cone clutch) and specific Volvo Penta models (SX-S, SX-C, SX-R, SX-M, DP-S, DP-S1, DP-SM). Cross-reference your original part number with the numbers provided (OMC/Volvo Penta 3854270/3858631, GLM 21962, Sierra 18-2771, Mallory 9-72930) to ensure an exact match.
Q: What are the signs that my U-Joint bellows needs replacement?
A: Common signs of failure include visible cracks, splits, or dry rot on the rubber. Water found inside the boat's bilge area or a grinding noise from the U-joint during operation are critical indicators that replacement is needed immediately to prevent costly drive failure.
Q: How often should the U-joint bellows be replaced?
A: It is recommended to inspect the bellows annually and replace them every 3-5 years as part of a regular preventative maintenance schedule, or immediately if any signs of wear, aging, or damage are found.
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?
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Quality Assured: As a trusted manufacturer for over 20 years, we supply top marine brands globally.
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Fast Global Shipping: Free delivery worldwide in 5–15 days.
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Direct from Manufacturer: Competitive pricing without compromising quality.