Sierra 18-21005K
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Sierra 18-21005K Product Description
Keep your boat's sterndrive running smoothly on the water with a reliable gimbal bearing kit designed for Mercury outboards and MerCruiser drives. This high-performance replacement tackles the wear and tear from constant saltwater exposure and high-RPM operation, ensuring your transom assembly stays sealed and vibration-free.
Key Features and Why It Matters
- Precision-Engineered Components: Includes top-grade bearings, seals, and hardware matched to original specs for a perfect fit and long-lasting durability against corrosion and friction.
- Complete Kit: Everything you need in one package—upper and lower bearings, O-rings, bellows clips, and lubricant—to minimize downtime during replacement.
- Corrosion-Resistant Materials: Built with marine-grade stainless steel and synthetic rubbers that withstand harsh marine environments, extending service life even in brackish or saltwater conditions.
- Easy Maintenance Access: Simplifies routine inspections and replacements, helping prevent costly failures like water intrusion or drive misalignment.
Boat owners swear by these kits for restoring that like-new pivot point between the engine and outdrive, reducing noise, and boosting overall handling precision during turns and docking.
Perfect Fit for Popular Mercury Models
This gimbal bearing kit slots right into a wide range of Mercury sterndrives, making it a go-to upgrade for weekend warriors and professional mechanics alike. It's engineered as a direct replacement for common setups on Alpha Generation I and II drives, early Bravo models, and select outboards with transom-mounted gimbal rings.
Before diving in, double-check your engine's serial number range to confirm compatibility—typically covering mid-1980s through early 2000s MerCruiser installations. Pro tip: Pair it with a fresh gimbal bearing housing inspection to catch any scored surfaces that could shorten the new kit's lifespan.
Step-by-Step Installation Tips from Seasoned Mechanics
- Prep Work: Tilt the drive up, drain fluids, and secure the boat on a stable trailer or lift. Wear safety gear and work in a well-ventilated area.
- Disassembly: Remove the trim cylinders, exhaust bellows, and shift cable. Use a gimbal bearing puller tool to extract the old bearings without damaging the housing.
- Clean Thoroughly: Wipe down the gimbal ring and housing with a non-residue cleaner to remove old grease, salt buildup, and debris.
- Install New Kit: Press in the upper and lower bearings using an installation tool, add O-rings and seals per the diagram, then apply marine grease liberally.
- Reassembly and Test: Reconnect everything, lower the drive, and run a sea trial to check for leaks, smooth pivot action, and no unusual vibrations.
Expect 2-4 hours for a DIY job if you're handy; otherwise, a certified shop ensures warranty peace of mind. Always torque to spec and use thread locker on fasteners.
Long-Term Care to Maximize Performance
A fresh gimbal bearing kit is your foundation, but regular upkeep keeps it performing. Inspect annually or every 100 hours: Look for play in the gimbal ring, cracks in bellows, or grease weeping. Flush with freshwater after every saltwater trip, and repack bearings during off-season storage. This simple routine can double your drive's reliability and save thousands in repairs.
Why Boaters Trust This Aftermarket Solution
Unlike stock parts that wear out predictably, this kit draws from decades of real-world testing on rough seas and tournament circuits. It's a smarter pick for reliability without compromise—delivering OEM-level fitment at a fraction of dealer costs. Join thousands of satisfied captains who've ditched leaks and rattles for quiet, confident cruises.
Frequently Asked Questions
What does a gimbal bearing kit do on a Mercury sterndrive?
It supports the smooth pivoting of the outdrive on the transom, preventing water entry and reducing vibration while allowing precise steering control.
How do I know if my gimbal bearing needs replacement?
Signs include steering play, whining noises under load, water in the bellows, or visible grease leaks around the transom assembly.
Is this kit compatible with Alpha Gen II drives?
Yes, it fits most Mercury Alpha One Gen II and compatible Bravo sterndrives; verify by serial number for exact match.
What tools are required for installation?
Essential tools include a gimbal bearing puller/installer set, torque wrench, seal protectors, and marine grease. A service manual helps too.
Can I install this myself without a lift?
Absolutely, on a trailer with the drive tilted up. Just ensure stability and have a helper for heavy lifting.
How often should I replace the gimbal bearings?
Every 3-5 years or 300-500 hours in saltwater; sooner if you notice wear symptoms.
Does it come with a warranty?
Most aftermarket kits offer a limited warranty against defects; check specifics with your supplier.
Save $17 when you buy the Sierra 18-21005K for only $92 from NVN Marine! Same day shipping before 3pm.
Sierra 18-21005K Technical Specifications
| Type: | |
|---|---|
| Vendor: |
Sierra Engine Parts |
| Weight: |
1.51 lb |
Sierra 18-21005K User Reviews
Sierra 18-21005K Shipping & Return
| Shipping Weight: |
1.51 lb |
|---|---|
| Box Sizes: |
2.00 (h) x 4.00 (w) x 4.00 (l) |
| Cubic Feet: |
32.0 |
| Returnable: |
Yes |
For detailed shipping policy please check our Shipping Policy and you can find our Return and Refund Policy here.