Mercury MerCruiser Quicksilver Cotter Pin 34212 | Superseded to 54929
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Mercury MerCruiser Quicksilver Cotter Pin 34212 | Superseded to 54929
Original Part Number: 34212 (service format: 18-34212)
Current Replacement: 54929 (service format: 18-54929)
Brand: Mercury / Quicksilver
Product Type: OEM Cotter Pin / Retaining Pin
System: MerCruiser Steering & Transom / Gimbal Housing
Quantity Required: 1 per applicable assembly
GTIN (34212): 745061137042 | GTIN (54929): 745061159587
Approximate Weight: 5 g
What This Part Does
The 34212 is a genuine Mercury OEM cotter pin used to retain the lower swivel pin in MerCruiser gimbal-housing assemblies and in selected power-steering actuator and steering sleeve applications. As a locking component, it prevents the swivel pin from backing out under load and vibration. Mercury has superseded 34212 to current cotter pin 54929 — if your parts manual lists 34212, 54929 is the current ordering number.
This is not a propeller cotter pin. 34212 / 54929 is specifically documented in MerCruiser steering and transom hardware — confirm the exact assembly and diagram position before ordering.
Compatible Applications
Confirm the exact MerCruiser drive, transom assembly, and steering diagram before ordering. Mercury uses several different cotter pins in nearby steering and transom hardware.
- MerCruiser gimbal housing / gimbal ring assemblies — lower swivel-pin retaining position
- MerCruiser power-steering cylinder / actuator assemblies
- Steering sleeve and related steering linkage assemblies
Fitment Notice
Mercury uses several different cotter pins in nearby steering and transom locations. For example, cotter pin 46950 appears on selected clevis-pin positions, while 34212 / 54929 is used at the lower swivel-pin or steering-sleeve location. Confirm by the exact diagram position and assembly before ordering.
Related Assembly Components
In lower swivel-pin applications, Mercury diagrams commonly show the following components at the same assembly position:
- 8M0073409 — Lower swivel pin
- 54929 — Cotter pin (current number for 34212)
- 32518 — Lower swivel-pin washer
Inspect the lower swivel pin, gimbal-ring and gimbal-housing bores, washer, and surrounding corrosion when replacing the cotter pin.
When to Replace
- Cotter pin has been removed during any steering or transom service
- Pin legs are fatigued, repeatedly bent, or distorted
- Corrosion is visible on the pin
- Lower swivel pin or steering hardware is being serviced
- Pin is missing from the assembly
A cotter pin is a single-use locking component — do not reuse a pin that has been removed or bent. Replace it any time the assembly is disturbed.
Installation Notes
- Install the replacement cotter pin in the same orientation shown in the applicable Mercury MerCruiser service diagram
- Bend the legs to lock the pin in place — do not over-bend to the point of stress cracking the pin material
- While the assembly is apart, inspect the lower swivel pin for wear, corrosion, or scoring and replace if necessary
- Apply corrosion protection to the swivel pin and surrounding hardware per the Mercury service procedure
- Follow the applicable Mercury MerCruiser service manual for torque specifications and reassembly sequence
Part Number Cross-Reference
- Original OEM: 34212 / 18-34212
- Current replacement: 54929 / 18-54929
- Supersession: 34212 → 54929
- Additional earlier references (same cotter pin family): 34159, 24552, 49324
- GTIN (34212): 745061137042
- GTIN (54929): 745061159587
Technical FAQ
Q: What is the current replacement for 34212?
A: Mercury has superseded 34212 to 54929 (service format 18-54929). If your parts manual, diagram, or older order history shows 34212, order 54929 as the current equivalent.
Q: Can I reuse the old cotter pin?
A: No. Cotter pins are single-use locking components. Once removed and bent back, the metal is fatigued and the pin will not provide reliable retention. Replace with a new 54929 any time the assembly is opened.
Q: Is this the same as a propeller cotter pin?
A: No. Mercury uses different cotter pins at different locations. The 34212 / 54929 is specifically documented in MerCruiser steering and gimbal-housing assemblies. Propeller shaft cotter pins are a different Mercury part number. Always confirm by diagram position.
Parts Desk Insights
Best use case: Order 54929 (the current number for legacy 34212) when servicing a MerCruiser gimbal housing, lower swivel pin, or steering assembly where the existing cotter pin was removed or is showing corrosion. Keep a spare in the tool kit — a cotter pin is always a single-use part and should be replaced every time the assembly is opened.
Common issues: The most common mistake is reusing the old cotter pin after reassembly, which risks the swivel pin backing out under load. A second common issue is ordering by the legacy number 34212 when the current service number 54929 is what dealers stock — both refer to the same current part. Also confirm the diagram position: Mercury uses different cotter pins at nearby locations in the same steering and transom assembly, and ordering the wrong one is an easy error without checking the diagram.
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
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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:
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