Sierra 18-9218 Drive Shaft, Replaces 59830A5, for Mercruiser Alpha One/Gen II Stern Drives

The Sierra 18-9218 is a drive shaft engineered for Mercruiser Alpha One and Gen II stern drive units, built as a direct replacement for OEM number 59830A5. It fits Mercruiser R, MR, and Alpha One Gen II drive units with serial number 0K999999 and below, covering the 1971-1997 production span. The drive shaft transmits engine power from the transom assembly through the drive unit to the propeller shaft, and is a wear item that should match OEM dimensions and material specification for correct engagement with the U-joints and yoke assemblies in the drive train.

This component is manufactured to meet or exceed the specification of the original equipment part it replaces, and is intended to restore proper drive-line alignment and power transfer on stern drive units that use this driveshaft configuration. It measures 24 x 4.25 x 4.25 inches and weighs 11.26 pounds.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-9218
• Product Type: Drive Shaft
• Weight: 11.26 pounds
• Product Dimensions: 24 x 4.25 x 4.25 inches
• Finish: Machined
• OEM Cross-Reference: 59830A5

Fitment

• Mercruiser Alpha One and Gen II stern drive units
• Applies to R, MR, and Alpha One Gen II drive units with serial number 0K999999 and below
• Production years 1971-1997

Replaces (OEM)

• 59830A5

Frequently Asked Questions

What does the Sierra 18-9218 drive shaft fit? The Sierra 18-9218 fits Mercruiser Alpha One and Gen II stern drive units, specifically R, MR, and Alpha One Gen II drives with serial number 0K999999 and below, covering the 1971-1997 production span.

Is the 18-9218 a direct replacement for OEM part 59830A5? Yes, the Sierra 18-9218 drive shaft is a direct replacement for OEM number 59830A5.

What are the dimensions of this drive shaft? The Sierra 18-9218 measures 24 x 4.25 x 4.25 inches.

How much does the 18-9218 drive shaft weigh? It weighs 11.26 pounds.

What finish does the Sierra 18-9218 have? This drive shaft has a machined finish.

Will the 18-9218 work on a serial number above 0K999999? No, the Sierra 18-9218 is designated for R, MR, and Alpha One Gen II drive units with serial number 0K999999 and below; drive units above that serial number use a different part.

Does Sierra offer a warranty on the 18-9218 drive shaft? Sierra parts, including the 18-9218 drive shaft, are covered under Sierra's standard customer satisfaction warranty.

What is the difference between the 18-9218 and the original Mercruiser drive shaft? The 18-9218 is manufactured to meet or exceed the specification of the original 59830A5 drive shaft it replaces, so fit and power transfer function match the OEM part.

Is this part sold as a complete assembly? The 18-9218 is a single drive shaft component; related drive train parts such as U-joints, center sockets, and yoke couplers are sold as separate part numbers.

What years of Mercruiser stern drives use the 18-9218? The 18-9218 drive shaft applies to Mercruiser Alpha One and Gen II drive units built between 1971 and 1997, up to serial number 0K999999.

Can I install the 18-9218 myself? The Sierra 18-9218 drive shaft is a stern drive component installed as part of the drive unit's internal driveline, and installation should follow the drive unit service procedure for the Alpha One/Gen II housing.