Sierra Drain Screw 18-2371, M8-1.25 Thread, Replaces 688-45341-00-00, Pack of 50

The Sierra Drain Screw 18-2371 is an M8-1.25 thread drain screw used to seal the drain and fill ports on marine lower units and gearcases. It is sold in a pack of 50, making it a practical stock item for shops, marinas, and service techs who perform routine gear lube changes and need a reliable supply of correctly sized screws on hand. The screw pairs with Sierra Gasket 18-4698, which creates the seal against the housing and should be replaced along with the screw each time the drain or fill plug is removed to prevent gear lube leaks. Installing a proper drain screw with a fresh gasket is a small but critical step in gearcase maintenance, since a worn or damaged sealing surface can allow lubricant to seep out or water to enter the housing, leading to costly internal damage. This part number is intended as a direct equivalent for the OEM numbers listed below, so it can be used as a drop-in replacement when servicing units originally fitted with those screws. Keeping a supply of these screws and matching gaskets on hand simplifies routine maintenance and helps ensure a proper, leak-free seal every time a lower unit is drained or refilled.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-2371
• Thread Size: M8-1.25
• Package Quantity: Pack of 50
• Weight: 0.01 pounds
• Compatible Gasket: Sierra 18-4698
• UPC: 808282185541
• OEM Cross-Reference: 688-45341-00-00, 688-45341-10-00

Replaces (OEM)

• 688-45341-00-00
• 688-45341-10-00

Frequently Asked Questions

What thread size is the Sierra 18-2371 drain screw? The Sierra 18-2371 drain screw has an M8-1.25 thread.

How many screws come in a pack? Sierra 18-2371 is sold in a pack of 50 drain screws.

Does the Sierra 18-2371 come with a gasket? No, the screw itself does not include a gasket, but it is designed to use Sierra Gasket 18-4698, which should be installed with it to create a proper seal.

What OEM part numbers does the 18-2371 replace? The 18-2371 drain screw replaces OEM numbers 688-45341-00-00 and 688-45341-10-00.

How much does the 18-2371 drain screw weigh? Each unit is listed at 0.01 pounds, reflecting the small size of an individual drain screw.

Can this screw be used for both drain and fill ports? Yes, the Sierra 18-2371 is used as a drain and fill screw on lower unit and gearcase housings that use the M8-1.25 thread and match the listed OEM numbers.

Is a new gasket required every time the drain screw is removed? It is recommended to replace the gasket, such as Sierra 18-4698, whenever the 18-2371 drain screw is removed to maintain a leak-free seal.

Is the Sierra 18-2371 an OEM or aftermarket part? The 18-2371 is a Sierra-brand replacement part manufactured as an equivalent to OEM numbers 688-45341-00-00 and 688-45341-10-00.

What is included when ordering this item? Ordering the Sierra 18-2371 provides 50 individual drain screws; the matching gasket, Sierra 18-4698, is a separate part.

Why buy drain screws in a pack of 50? A pack of 50 Sierra 18-2371 screws is intended for shops and technicians who regularly service lower units and need a ready supply of correctly sized drain and fill screws.