Mercury - Cotter Pin - 18-54929
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The Mercury Quicksilver Cotter Pin 18-54929 is an OEM mechanical locking fastener used in select MerCruiser sterndrive transom and swivel assemblies. It helps retain critical pivot hardware such as gimbal ring, hinge, and lower swivel pin components so they remain locked in position under vibration and steering load.
Key Features
- Genuine Mercury/Quicksilver cotter pin
- Part number: 18-54929
- Also referenced as 54929
- Marine-grade split locking fastener
- Approximate dimensions: 3.00" L x 0.50" W x 0.25" H
- GTIN / UPC: 745061159587
- Used in select gimbal housing, gimbal ring, and lower swivel pin locations
Drive Compatibility
Used on select MerCruiser Alpha One Generation II and Bravo I / II / III sterndrive transom assemblies, including lower swivel pin and gimbal housing attachment locations where this cotter pin is shown in the Mercury parts diagram.
Serial Number Fitment Notice
Verify fitment by drive/transom serial number and parts diagram before ordering. Cotter pin size and location can vary by drive generation, gimbal housing design, swivel shaft hardware, and production range.
When This Part Needs Replacement
Replace this cotter pin anytime it is removed, bent, corroded, cracked, missing, or damaged during gimbal ring, swivel pin, steering, or transom assembly service.
Installation Notes
Cotter pins are designed to deform during installation and should not be reused. Install a new pin after the related hardware is properly seated and torqued, then bend the legs securely according to Mercury service procedure.
Alternate/Superseded Part Numbers
Replaces Mercury 18-34212, 34212, 34159, 24552, and 49324. Primary references: 18-54929 and 54929.
Parts Desk Insight
A cotter pin is inexpensive, but it is a safety-critical retainer. Reusing an old pin after steering or transom service can leave important pivot hardware less secure than it should be.
Shipping: Ships same or next day for fast Canada wide shipping. ⚓
Shipping information
In-stock and OEM parts: ship same or next business day.
Locally warehoused items: ship within 3–4 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.