Power Trim Ram Cylinder O-Ring Seal Kit – Fits MerCruiser Alpha One, Gen II, Bravo & R/MR Drives (Replaces 25-87400A2)
Power Trim Ram Cylinder O-Ring Seal Kit – Fits MerCruiser Alpha One, Gen II, Bravo & R/MR Drives (Replaces 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 Ram Cylinder O-Ring Seal Kit – Fits MerCruiser Alpha One...
Product Details
This Power Trim Ram Cylinder O-Ring Seal Kit is designed to rebuild the hydraulic trim cylinders on a wide range of Mercury/MerCruiser stern drives, including Alpha One (Gen I & II), Bravo (I, II, & III), R, and MR models. It provides all the necessary seals to restore hydraulic integrity and prevent fluid leaks in one cylinder.
The kit serves as a direct replacement for OEM and aftermarket part numbers, including Mercury/MerCruiser 25-87400A2, Sierra 18-2649, GLM 87400, and HeuroFosh 87400.
- Engineered for direct-fit installation.
- Made from high-grade synthetic rubber for durability.
- Includes all seals required to service one complete trim cylinder.
Part Number Matrix
Use this matrix to confirm equivalent references across OEM and aftermarket.
| Brand | Part Number |
|---|---|
| Mercury/MerCruiser | 25-87400A2 |
| Sierra | 18-2649 |
| GLM | 87400 |
| HeuroFosh | 87400 |
Engine & Model Compatibility
Confirm your engine model/year in the table below.
This seal kit is compatible with all years for the listed MerCruiser stern drive models.
| Brand | Model | Years | OEM Part No. |
|---|---|---|---|
| MerCruiser | Alpha One | All | 25-87400A2 |
| MerCruiser | Alpha One Gen II | All | 25-87400A2 |
| MerCruiser | Bravo I | All | 25-87400A2 |
| MerCruiser | Bravo II | All | 25-87400A2 |
| MerCruiser | Bravo III | All | 25-87400A2 |
| MerCruiser | R | All | 25-87400A2 |
| MerCruiser | MR | All | 25-87400A2 |
Technical Specs
- Product Type
- Trim Cylinder Seal Rebuild Kit
- Installation
- Direct replacement
- Connection
- Hydraulic
- Housing Material
- Synthetic rubber o-rings and seals
- Dimensions
- Complete kit for one cylinder
- Other Technical Attributes
- Includes all seals needed for one trim cylinder
What’s in the Box
- A complete set of synthetic rubber o-rings and seals to rebuild one trim ram cylinder.
Installation Notes
- Safely support the stern drive in the fully raised position.
- Thoroughly clean the area around the trim ram cylinder to prevent contamination.
- Place a drain pan under the assembly and disconnect the hydraulic lines.
- Remove the retaining pins or bolts to detach the cylinder from the stern drive.
- Carefully disassemble the cylinder, noting the orientation of all internal components and seals.
- Remove all old o-rings and seals, and clean the internal components and cylinder bore.
- Lubricate the new seals with hydraulic fluid and install them in the correct grooves.
- Reassemble the cylinder, ensuring all components are properly seated.
- Reinstall the cylinder onto the stern drive and reconnect hydraulic lines.
- Refill the hydraulic reservoir and bleed the system of air according to the manufacturer's procedure. Check for leaks.
Troubleshooting & FAQ
How do I know if my trim cylinder seals are failing?
Common signs include visible hydraulic fluid leaks around the cylinder rods, a "spongy" or slow trim response, or the stern drive slowly drifting down from its trimmed position. You may also notice a drop in the hydraulic fluid level in the reservoir.
How many cylinders does one kit repair?
This kit contains all the necessary seals to rebuild and service one single trim ram cylinder. If you need to service both cylinders on your stern drive, you will need to purchase two kits.
Will this kit fit my specific MerCruiser model?
This kit is designed for a broad range of MerCruiser drives, including Alpha One (Gen I & II), Bravo (I, II, III), R, and MR models of all years. Always verify your part number against the Part Number Matrix to ensure an exact match.
What typically causes trim seals to fail?
Seals can degrade over time due to age, exposure to UV light and marine environments, contamination of the hydraulic fluid, or physical damage to the cylinder rod (e.g., nicks or corrosion) which can tear the seal.
Is this a complete kit for a rebuild?
Yes, this kit includes all the o-rings and seals required to fully rebuild one trim cylinder. It does not include hard parts like the piston, rod, or cylinder body.
Are any special tools required for installation?
You will need standard mechanical tools, a spanner wrench to remove the end cap of the cylinder, and picks to remove the old seals. Access to your vessel's service manual for specific torque values and bleeding procedures is highly recommended.
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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