Description

The MDX-7 is a sacrificial zinc shaft-style anode designed to protect outboard and inboard drivetrain components from galvanic corrosion. Installed on the shaft or running gear, it corrodes first—preserving critical metal components like shafts, propellers, and brackets.

Manufactured from marine-grade zinc alloy, it is specifically suited for saltwater environments, where zinc provides stable and predictable corrosion protection.

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Key Features

• MDX-7 shaft-style zinc anode
• Designed for 1-1/2″ shaft applications
• Marine-grade zinc alloy construction
• Protects shafts, propellers, and underwater metals
• Two-piece clamp-style design (typical configuration)
• Reliable performance in saltwater use

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Application / Compatibility

Designed for:

• 1-1/2″ propeller shafts
• Inboard and some outboard drivetrain setups
• Shaft-driven vessels

Common on:

• Inboard boats
• Sailboats
• Commercial and recreational vessels

Protects:

• Shafts
• Struts
• Prop hubs and nearby hardware

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Serial Number / Fitment Notice

Always confirm:

• Shaft diameter (1-1/2″)
• Clearance for installation
• Correct MDX series sizing

Correct sizing is critical for proper clamping and corrosion protection.

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When This Part Needs Replacement

• Anode is 50% or more consumed
• Loose fit on shaft
• Uneven or accelerated wear
• Routine haul-out inspection

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Installation Notes

• Install tightly around clean shaft surface
• Ensure full metal-to-metal contact
• Do not paint the anode
• Position away from bearings and prop for clearance
• Recheck tightness after initial run

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Alternate / Cross-Reference Part Numbers

• MDX-7 (Reliance / aftermarket reference)
• Comparable Martyr shaft anode sizes available
• Aluminum equivalent available for mixed water use

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Parts Desk Insight

Shaft anodes like the MDX-7 are your primary defense for running gear. If these are wearing quickly, it’s usually a sign the system is working—not failing—but it’s worth checking bonding and stray current if wear is excessive.

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Shipping

Shipping: Ships same or next day for fast Canada wide shipping.