Mercury MerCruiser SeaCore Port Trim Cylinder Assembly — OEM 8M0128692 | Bravo One, Two, Three
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Mercury MerCruiser SeaCore Port Trim Cylinder Assembly — OEM 8M0128692 | Bravo One, Two, Three
This genuine OEM port-side power-trim cylinder is the SeaCore-configuration replacement for selected MerCruiser Bravo sterndrives. It works together with the starboard cylinder to raise, lower, and hold the sterndrive at the correct trim angle under hydraulic pressure. If the port side of your Bravo trim system is leaking, won’t hold trim position, or has a damaged rod or cylinder body, 8M0128692 is the OEM replacement — but confirming the SeaCore configuration is critical before ordering, as standard Bravo drives use a different port-side cylinder.
Part Information
- OEM Part Number: 8M0128692
- Brand: Mercury / MerCruiser
- Official Product Type: Port hydraulic power-trim cylinder assembly
- Configuration: SeaCore
- Position: Port (left side)
- Matching Starboard Cylinder: 8M0128693 (SeaCore starboard side)
- System: Hydraulic power-trim system
- Quantity: One port cylinder per trim assembly
- GTIN / UPC: Not on file — verify at time of order
Compatible Applications
- MerCruiser Bravo One — SeaCore trim-cylinder configuration
- MerCruiser Bravo Two — SeaCore trim-cylinder configuration
- MerCruiser Bravo Three — SeaCore trim-cylinder configuration
- MerCruiser Bravo X One / Two / Three — SeaCore configuration
- MerCruiser Bravo XR One / Three — SeaCore configuration
- MerCruiser Bravo XR SportMaster — SeaCore configuration
- Selected high-performance and integrated transom applications using this SeaCore port cylinder
- Important: Confirm the drive model, transom assembly, and trim-cylinder configuration before ordering — standard (non-SeaCore) Bravo drives use a different port trim cylinder
Related Parts
- Mercury MerCruiser SeaCore Starboard Trim Cylinder Assembly — 8M0128693 (matching starboard cylinder)
- Mercury MerCruiser Bravo Trim Cylinder Assembly Starboard — 8M0132610 (standard non-SeaCore starboard reference)
When to Replace
- Hydraulic fluid leaking from the cylinder body, rod seal, or fitting connections
- Sterndrive will not hold trim position and diagnosis points to the port cylinder
- Cylinder rod is bent, scored, or corroded beyond service limits
- Cylinder body is cracked or physically damaged
- Internal cylinder wear causing erratic or weak trim operation on the port side
Installation Notes
- Inspect hydraulic hoses, fittings, mounting pins, anodes, and mating hardware while the cylinder is removed
- Replace hoses and seals as needed rather than reusing worn components
- Follow the applicable Mercury service procedure for cylinder installation and hydraulic-system bleeding
- Verify smooth, full-range trim operation on both port and starboard sides and check for fluid leakage before returning the drive to service
- Torque all hydraulic fittings to Mercury specification to prevent leaks under pressure
Technical FAQ
What is the difference between the SeaCore and standard port trim cylinder?
SeaCore trim cylinders are built with a corrosion-protection package for saltwater environments, including specific cylinder materials and coatings. Standard Bravo drives use a different port-side cylinder. The two configurations are not interchangeable — always confirm whether your transom assembly is SeaCore or standard before ordering.
Should I replace both port and starboard cylinders at the same time?
It is strongly recommended. If one cylinder is leaking or failing, the other has experienced the same service hours and conditions. Replacing both together during the same service visit avoids a repeat job and ensures balanced trim performance. The matching starboard cylinder is 8M0128693.
How do I confirm this is the correct cylinder for my drive?
The most reliable method is to match the existing cylinder’s part number or check the transom assembly number against Mercury’s parts catalog. Drive model alone (e.g., Bravo Three) is not sufficient, because both SeaCore and standard cylinders are listed for the same drive families.
Parts Desk Insights
Port and starboard trim cylinders on Bravo drives almost always need to be replaced together — if a customer comes in for one cylinder, the recommendation should always be to do both sides. The SeaCore vs. standard configuration mix-up is the most common ordering error on Bravo trim cylinders, and it’s easy to make because the drive model names are the same across both configurations. The safest confirmation is the existing cylinder part number. Browse the full MerCruiser Marine Engine Parts collection for related sterndrive and trim components.
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 1-3 business days.
Special-order items: timeline confirmed after order.
Returns & warranty
Returns & Satisfaction Guarantee
We stand firmly behind the quality of every product we sell. Your confidence matters to us — and we back it with a straightforward 30-Day Satisfaction Guarantee.
If you are not fully satisfied, you may request a return within 30 days of delivery. All returns must receive pre-approval prior to being sent back. Unauthorized returns will not be accepted.
To qualify for a return:
Item must be in new, unused condition
Product must be in its original packaging
All parts, components, hardware, manuals, and accessories must be included
Packaging must be undamaged and suitable for resale
Important:
Electronics are strictly inspected. No returns on open-box electronics. Exceptions may apply only with prior written approval. Any electronic unit that has been installed, powered, activated, or altered may not be eligible for return.
We are serious about product integrity — and equally serious about taking care of our customers. If there is ever a product issue, contact us immediately so we can make it right.
For return authorization, please contact our support team before shipping anything back.