Power Trim Cylinder Seal Kit – Fits MerCruiser R, MR, Alpha One Gen I & II, Bravo I, II, III (Replaces 87400A2, 25-87400A2)

Power Trim Cylinder Seal Kit – Fits MerCruiser R, MR, Alpha One Gen I & II, Bravo I, II, III

This power trim cylinder seal kit is designed for a wide range of MerCruiser sterndrive models, including R, MR, Alpha One (Gen I 1983–1990), Alpha One Gen II (1991 and up), Bravo I, II, III, Bravo X, XR, and Sportmaster trim cylinders.

It serves as a direct replacement for multiple OEM and aftermarket part numbers, ensuring a precise fit and reliable performance for your hydraulic trim system.

• Installation: Direct replacement for a hassle-free installation.
• Material: Made from high-grade rubber to ensure a durable, long-lasting seal against leaks.
• Contents: Includes a complete set of O-rings and seals to service one trim 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. For Mercury owners, here’s a guide to help you identify your engine’s serial/model: Mercury Serial Number Guide. You can also review exploded diagrams to verify part numbers: Mercury Parts Diagrams & Catalog.

Technical Specifications

Package Contents

Note: This kit contains all necessary seals for one (1) trim cylinder. If you are servicing both sterndrive cylinders, you must purchase two kits.

• 1 x Power Trim Seal Kit (Replaces OEM 25-87400A2)

Installation Guide

Professional installation is recommended. The following are general steps for replacing trim seals:

1. Raise the sterndrive to the full "up" position and secure it with the trailer lock mechanism.
2. Clean the area around the trim cylinder end caps to prevent dirt and debris from entering the hydraulic system.
3. Using an appropriate spanner wrench, carefully loosen and remove the cylinder end cap. Be prepared for some hydraulic fluid to spill.
4. Slide the trim rod out far enough to access and remove the old seals from the piston and the end cap. Pay close attention to their order and orientation.
5. Thoroughly clean the grooves on the piston and inside the end cap.
6. Lubricate the new seals with fresh hydraulic trim fluid before installation to prevent damage.
7. Carefully install the new seals, ensuring they are properly seated in their grooves without being twisted or nicked.
8. Re-insert the rod and re-install the end cap, tightening it to the manufacturer's recommended torque specification.
9. Top off the hydraulic fluid reservoir and bleed the system by cycling the trim up and down several times to remove any trapped air.
10. Check for any leaks and verify smooth, consistent trim operation.

Troubleshooting & FAQ

How do I confirm this seal kit fits my MerCruiser sterndrive?
This kit is designed for a broad range of MerCruiser sterndrives, including the R, MR, Alpha One (Gen I & II), and all Bravo series (I, II, III, X, XR). To ensure a perfect match, please consult the "Compatible Engine Models" table above and cross-reference your model and year. Also, verify that your existing part number matches one of the numbers listed in our cross-reference table, such as 25-87400A2.

What are the signs that my trim cylinder seals are failing?
Common symptoms include visible hydraulic fluid leaks around the cylinder rods or end caps, a "spongy" or jerky trim movement, or the sterndrive slowly drifting down from its trimmed position. These issues indicate that the seals are no longer holding pressure effectively and should be replaced.

Does this kit service one or both trim cylinders?
This kit contains all the seals required to rebuild one single trim cylinder. MerCruiser sterndrives have two trim cylinders, so if you plan to service both, you will need to purchase two of these kits.

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.