Sierra 18-2599 Face Seal and Tool, Fits Alpha One Gen II Drives, Replaces 26-816575A2

The Sierra 18-2599 Face Seal and Tool is a drive seal designed for Alpha One Gen II sterndrives, supplied as a face seal along with the installation tool needed to seat it correctly. The face seal is a wear item inside the drive housing that maintains the seal between rotating and stationary components, and using the correct tool during installation helps the seal seat evenly and prevents damage that can occur when it is pressed in without one. The seal is molded from nitrile rubber or Viton, materials chosen for their resistance to marine lubricants, water intrusion, and the heat generated at the drive interface. Sierra manufactures this seal and tool to meet or exceed the specification of the original equipment part it replaces, and it is built to be interchangeable with the corresponding OEM and aftermarket part numbers used across Alpha One Gen II applications. The package includes one face seal and one tool, so no separate tool purchase is needed to complete the installation. This part is commonly replaced during drive seal service, prop shaft bearing carrier rebuilds, or general Alpha One Gen II maintenance where the face seal has begun to leak or show wear. Sierra backs this product with its standard customer satisfaction warranty.

Specifications

• Brand: Sierra
• Manufacturer Part Number: 18-2599
• Product Type: Face Seal and Tool
• Material: Nitrile rubber or Viton
• Package Quantity: 1
• Weight: 0.01 pounds
• UPC: 030999875105
• Fitment: Alpha One Gen II drives
• OEM Cross Reference: 26-816575A2

Fitment

• Alpha One Gen II drives

Replaces (OEM)

• 26-816575A2

Frequently Asked Questions

What does the Sierra 18-2599 fit? The Sierra 18-2599 Face Seal and Tool is designed for Alpha One Gen II sterndrives.

Is the 18-2599 the same as OEM part 26-816575A2? Yes, the Sierra 18-2599 is designed to be interchangeable with Mercruiser/Mercury OEM part 26-816575A2.

Does this part cross-reference to any other brands? Sierra 18-2599 is designed to be interchangeable with GLM 85590 and Mallory 9-3628, in addition to Mercruiser/Mercury 26-816575A2.

What is included in the package? One count of the face seal and one installation tool ship together in the Sierra 18-2599 package.

What material is the face seal made of? The Sierra 18-2599 face seal is molded from nitrile rubber or Viton, materials chosen for resistance to marine lubricants and water.

Do I need a special tool to install this seal? No separate tool purchase is needed; the Sierra 18-2599 package already includes the tool required to seat the face seal correctly.

How much does the Sierra 18-2599 weigh? The Sierra 18-2599 Face Seal and Tool weighs 0.01 pounds.

Is Sierra 18-2599 a genuine Sierra part or a generic aftermarket seal? It is a genuine Sierra-manufactured part, produced to meet or exceed the specification of the original equipment seal it replaces.

What is a face seal used for on a sterndrive? A face seal, like the Sierra 18-2599, seals the interface inside the Alpha One Gen II drive housing to keep water out and lubricant in around the rotating shaft.

Is the Sierra 18-2599 covered under warranty? Yes, the Sierra 18-2599 Face Seal and Tool is covered under Sierra's customer satisfaction warranty.