Mercury – Upper Gearcase Seal Kit – 26-32511A1

The Mercury Quicksilver Upper Gearcase Seal Kit 26-32511A1 is an OEM-style reseal kit for select legacy MerCruiser upper outdrive assemblies. This kit includes the seals, O-rings, and gaskets commonly required to reseal the drive shaft housing during upper gearcase service, pressure-leak repair, or full teardown maintenance.

Key Features

• Mercury/Quicksilver upper gearcase seal kit
• Part number: 26-32511A1
• Also referenced as 32511A1
• Designed for upper outdrive / drive shaft housing reseal service
• Includes oil seals, O-rings, and related gaskets
• Helps correct gear lube leaks and pressure-test failures in the upper gear housing
• Commonly includes components such as 26-32511, 26-823894, 26-965031, 25-32546, 25-70937, 25-55801, and 12-19183

Drive Compatibility

Fits select legacy MerCruiser #1, MR, and Alpha One Generation 1 sterndrives, commonly used from 1963 through 1990/1991 applications. Fits MerCruiser #1 / MR / Alpha configurations with serial number 1684188 and up, and 888 stern drive models from serial number 3106717 and up.

Serial Number Fitment Notice

Verify fitment by drive serial number and upper gear housing diagram before ordering. This kit is for legacy MerCruiser #1, MR, and Alpha One Gen 1 style drives and does not fit Alpha One Generation II drives.

When This Part Needs Replacement

Use this kit when resealing the upper gearcase, repairing a pressure or vacuum leak, replacing worn oil seals, servicing water-contaminated gear lube, or rebuilding the upper drive housing during teardown.

Installation Notes

Upper gearcase reseal work requires proper disassembly, seal removal tools, correct seal drivers, and pressure/vacuum testing after reassembly. Inspect shafts, sealing surfaces, bearing condition, top cover surfaces, and drain/fill screw gaskets during service. Replace any grooved or corroded mating surfaces before final assembly.

Alternate/Superseded Part Numbers

Primary Mercury references: 26-32511A1 and 32511A1. Common aftermarket interchanges include Sierra Marine 18-2648, GLM Marine 87500, and Mallory Marine 9-74303.

Parts Desk Insight

This is the right style of kit when the upper drive needs a complete reseal instead of replacing one seal at a time. The key detail is drive generation: Alpha One Gen 1 and Alpha One Gen II use different sealing layouts, so checking the drive serial number before ordering prevents an expensive mismatch.

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