Power Trim Cylinder Seal Kit – Fits MerCruiser R, MR, Alpha One, Bravo I, II, III (Replaces 87400A2, 25-87400A2)
Power Trim Cylinder Seal Kit – Fits MerCruiser R, MR, Alpha One, Bravo I, II, III (Replaces 87400A2, 25-87400A2) 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
Power Trim Cylinder Seal Kit – Fits MerCruiser R, MR, Alpha One, Br...
Product Details
This high-quality Power Trim Cylinder Seal Kit is designed for a wide range of MerCruiser sterndrive trim cylinders, including R, MR, Alpha One (Gen I 1983–1990), Alpha One Gen II (1991 and up), as well as Bravo I, II, III, Bravo X, XR, and Sportmaster models. It provides a reliable solution for repairing leaking or failing hydraulic trim cylinders.
This kit serves as a direct aftermarket replacement for MerCruiser part numbers 87400A2 and 25-87400A2, Sierra 18-2649, GLM 87400, and Quicksilver 87400A2.
- Direct-replacement installation requires no special modifications.
- Made from durable, high-grade rubber to resist the harsh marine environment.
- Includes a complete seal kit for servicing one (1) trim cylinder.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket brands.
| Brand | Part Number |
|---|---|
| MerCruiser | 87400A2 / 25-87400A2 |
| Quicksilver | 87400A2 |
| Sierra | 18-2649 |
| GLM | 87400 |
Engine & Model Compatibility
Confirm your engine model and year in the table below. This kit fits a wide variety of sterndrive and transom assembly models.
| Model | Years | OEM Part No. | Notes |
|---|---|---|---|
| R/MR/ALPHA ONE (Sterndrive) | 1983–1990 | 25-87400A2 | |
| R/MR/ALPHA ONE (Transom Assembly) | 1983–1990 | 25-87400A2 | |
| Alpha One Gen II | 1991–1995 | 25-87400A2 | |
| Alpha One Gen II | 1996–1997 | 25-87400A2 | |
| Alpha One Gen II | 1998 and up | 25-87400A2 | |
| Blackhawk | 1994–1995 | 25-87400A2 | |
| BRAVO One / Two / Three | All Years | 25-87400A2 | |
| BRAVO X One / Two / Three | All Years | 25-87400A2 | |
| BRAVO XR One / Three / Sportmaster | All Years | 25-87400A2 | |
| BRAVO XZ One | All Years | 25-87400A2 | |
| HI PERFORMANCE TRANSOM, INTEGRATED TRANSOM | All Years | 25-87400A2 |
Technical Specs
- Product Type
- Trim Cylinder O-Ring/Seal Kit
- Installation
- Direct Replacement
- Material
- Rubber
- Package Contains
- Complete seal kit for one (1) trim cylinder
- Color
- Black
What’s in the Box
- 1 x Power Trim Seal Kit (Replaces 25-87400A2)
Installation Notes
- Trim the sterndrive to the full "up" or "trailer" position and engage the safety lock.
- Disconnect the boat's battery to prevent any accidental activation of the trim system.
- Place a drain pan under the cylinder and disconnect the hydraulic lines. Be prepared to cap the lines to minimize fluid loss.
- Remove the upper and lower pivot pins or bolts securing the trim cylinder to the gimbal housing and sterndrive.
- Carefully maneuver the cylinder free from its mounting brackets.
- Using a proper spanner wrench, unscrew and remove the end cap (gland) from the cylinder body.
- Slide the piston rod assembly out of the cylinder barrel.
- Carefully remove all old seals and O-rings from both the piston and the end cap, noting their placement and orientation.
- Thoroughly clean all components with a suitable solvent and inspect for scratches, corrosion, or wear.
- Lightly lubricate the new seals with fresh hydraulic trim fluid and carefully install them in the correct grooves.
- Re-insert the piston assembly into the cylinder, re-install the end cap, and torque to the manufacturer's specification.
- Re-install the cylinder on the sterndrive, reconnect hydraulic lines, top off the reservoir, and bleed the system of air.
Troubleshooting & FAQ
How do I know if my trim cylinder seals are failing?
Common signs include visible hydraulic fluid leaking from the cylinder end caps, a slow or "spongy" trim response, or the sterndrive slowly "drifting" down from a trimmed position when the engine is off.
Does this kit service one or two cylinders?
This kit contains all the necessary seals to rebuild one (1) power trim cylinder. If you need to service both the port and starboard cylinders on your sterndrive, you must purchase two kits.
Is a special tool required for this job?
Yes, a pin spanner wrench is required to safely remove and reinstall the end cap on the trim cylinder without damaging it. Ensure you have the correct size wrench for your specific cylinder model before starting.
What causes trim seals to fail?
Seals wear out over time due to age, exposure to the elements (UV, saltwater), hydraulic pressure cycles, and contamination of the hydraulic fluid. Scratches on the cylinder rod can also damage seals and cause premature failure.
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 in 5–15 days.
- Manufacturer-Direct Value — Fair pricing without compromising on materials or QC.
Payment & Security
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