Trim/Tilt Cylinder Seal Kit – Fits OMC Cobra Stern Drive & Volvo Penta SX (Replaces 0985060, 3854247)

Trim/Tilt Cylinder Seal Kit – Fits OMC Cobra & Volvo Penta SX

This aftermarket seal kit is designed for rebuilding hydraulic trim and tilt cylinders on a wide range of OMC Cobra and Volvo Penta stern drives. It provides a direct-fit replacement for leaking or worn-out original seals, restoring hydraulic integrity and performance.

This kit is compatible with OMC Cobra stern drives from 1986–1998 (including King Cobra models) and Volvo Penta SX, DP-S, and DP-SM series drives. It directly replaces OEM part numbers OMC 0985060, 0778202, 3854247 and Volvo Penta 3854247.

• Engineered to rebuild trim/tilt cylinders with part numbers: 3852414, 3850683, 3885196, 3857470, 3857471.
• Manufactured with marine-grade materials for excellent resistance to salt water and corrosion.
• Each kit contains all the necessary seals, O-rings, and wipers to rebuild one hydraulic cylinder.

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.

OMC Cobra Stern Drive

Volvo Penta Stern Drive

Technical Specifications

Package Contents

This package includes a complete seal kit for one trim/tilt cylinder. To service both cylinders on a typical stern drive, you will need to purchase two kits.

• Includes a full set of replacement seals, O-rings, wipers, and backup rings.
• Direct replacement for cylinders compatible with OMC 0985060 / 0778202 / 3854247 and Volvo Penta 3854247.

Installation Guide

Professional installation is recommended. The following is a general guide:

1. Safety First: Lower the stern drive to the down position and support it securely with blocks. Disconnect the battery.
2. Access the Cylinder: Remove any covers or components obstructing access to the trim/tilt cylinder.
3. Remove Cylinder: Disconnect the hydraulic lines (plug them to prevent spills) and remove the cylinder mounting pins or bolts.
4. Disassemble Cylinder: Carefully disassemble the cylinder, taking note of the order and orientation of internal components. A vice may be needed.
5. Remove Old Seals: Using appropriate picks, remove all old seals, O-rings, and wipers from the piston and cylinder gland.
6. Clean and Inspect: Thoroughly clean all parts with a suitable solvent and inspect the cylinder bore and rod for scratches or damage.
7. Install New Seals: Lubricate the new seals with hydraulic fluid and carefully install them in their respective grooves.
8. Reassemble and Reinstall: Reassemble the cylinder and reinstall it on the stern drive, reconnecting hydraulic lines.
9. Bleed the System: Top off the hydraulic fluid reservoir and cycle the trim/tilt system up and down several times to bleed air. Check for leaks.

Troubleshooting & FAQ

How do I know if this seal kit will fit my stern drive?
First, check the Compatible Engine Models tables on this page to see if your model and year range are listed. Second, confirm that your OEM part number matches one of the numbers in the cross-reference list (OMC 0985060, 0778202, 3854247 or Volvo Penta 3854247). Finally, this kit is specifically for cylinders with part numbers 3852414, 3850683, 3885196, 3857470, or 3857471.

What are the signs my trim cylinder seals are failing?
Common symptoms include visible hydraulic fluid leaking from the cylinder ends, a "spongy" or weak trim response, or the stern drive slowly drifting down from a trimmed position. A gradual loss of hydraulic fluid in the reservoir is also a key indicator.

Does this kit service one or both trim cylinders?
This kit contains all the required seals to rebuild one single trim/tilt cylinder. Most stern drive applications have two cylinders, so you will need to order two kits to service the entire system.

OEM vs. Aftermarket?
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.

How fast do you ship and how much does it cost?
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.

What is your warranty and return policy?
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.