Sierra 18-2128 Center Socket for MerCruiser Alpha One, Bravo, MC-I, MC II, TS, IA/IB/IC and EZ, Gen II, and OMC Cobra Drives

The Sierra 18-2128 Center Socket is a stern drive coupling component that connects the drive shaft assembly to the U-joint, transferring power from the engine to the outdrive. It is a fit-specific part, meaning it is engineered to match particular drive units rather than serving as a universal fit across all stern drives, so confirming the correct application before ordering is important.

This Center Socket is designed for MerCruiser IA/IB/IC and EZ, MC-I, R, MR, Alpha One, and Gen II drives up to serial number 0L949778, as well as MerCruiser Bravo drives up to serial number 0M111207, MC II, and TS drives. It also fits all OMC Cobra sterndrives. Sierra states that each part it manufactures meets or exceeds the specifications of the original equipment part it replaces, making this Center Socket a direct functional replacement for the applicable OEM component.

The Center Socket ships as a single component and is sold individually. It weighs 2.04 pounds.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-2128
• Product Name: Center Socket
• UPC: 030999311467
• Weight: 2.04 pounds
• Unit Count: 1
• Fit Type: Fit-specific; confirm drive application before ordering

Fitment

• MerCruiser IA/IB/IC and EZ, MC-I, R, MR, Alpha One, and Gen II (serial number 0L949778 and below)
• MerCruiser Bravo (serial number 0M111207 and below), MC II, and TS
• All OMC Cobra sterndrives

Replaces (OEM)

• 393
• 735
• 393831

Frequently Asked Questions

What does the Sierra 18-2128 Center Socket fit? This Center Socket fits MerCruiser IA/IB/IC and EZ, MC-I, R, MR, Alpha One, and Gen II drives with serial number 0L949778 and below, MerCruiser Bravo drives with serial number 0M111207 and below, MC II, TS drives, and all OMC Cobra sterndrives.

Is the 18-2128 Center Socket a universal fit for all stern drives? No. Sierra designates part 18-2128 as a fit-specific component, so it is built for the listed MerCruiser and OMC Cobra drive applications rather than a one-size-fits-all fit, and confirming your drive model and serial number before ordering is recommended.

What OEM part numbers does the Sierra 18-2128 Center Socket replace? The Sierra 18-2128 Center Socket cross-references to OEM numbers 393, 735, and 393831.

How much does the Sierra 18-2128 Center Socket weigh? The Sierra 18-2128 Center Socket weighs 2.04 pounds.

How many Center Sockets come in the package? Part 18-2128 is sold as a single Center Socket, with a unit count of 1.

Does the Sierra Center Socket perform the same as the original equipment part? Sierra states that the 18-2128 Center Socket meets or exceeds the specifications of the original equipment part it replaces, so it functions as a direct replacement in its listed applications.

Will the 18-2128 Center Socket fit a MerCruiser Bravo drive with a serial number above 0M111207? The 18-2128 Center Socket is listed for MerCruiser Bravo drives with serial number 0M111207 and below; drives above that serial number are not covered by this fitment.

Does the Sierra 18-2128 fit OMC Cobra sterndrives? Yes, the Sierra 18-2128 Center Socket fits all OMC Cobra sterndrives.

What is a Center Socket used for on a stern drive? A Center Socket, such as Sierra part 18-2128, is a coupling component within the drive shaft assembly that connects to the U-joint to transmit engine power to the stern drive unit.

Is installation of the Sierra 18-2128 Center Socket something I can do myself? Because the 18-2128 Center Socket is part of the drive shaft coupling assembly and fit-specific to the drive model, Sierra recommends consulting an authorized dealer to confirm the correct fit and installation for your specific drive.

Does the Sierra 18-2128 fit MerCruiser Alpha One drives? Yes, the Sierra 18-2128 Center Socket is listed for MerCruiser Alpha One drives, along with IA/IB/IC and EZ, MC-I, R, MR, and Gen II drives at or below serial number 0L949778.