Choosing the Right MerCruiser Gimbal Bearing

MerCruiser Parts Guide
Written By Laura California

If you’ve ever searched for a MerCruiser gimbal bearing, you’ve probably run into a maze of conflicting information. Different sellers list different part numbers, charts don’t match each other, and many references online point to superseded part numbers that no longer exist in Mercury’s current catalog. With all of that mixed together, it’s no surprise boaters end up confused about which OEM bearing their drive actually needs.

Greaseable vs. Sealed Gimbal Bearing

MerCruiser originally used greaseable gimbal bearings, and those transom assemblies were drilled with a grease passage that fed the bearing through a grease zerk on the outside of the housing. When Mercury transitioned to the permanently sealed “Perma‑Lube” bearing, the bearing no longer relied on that external grease passage for service. Many older housings still have the grease zerk fitting, so Mercury still includes a small plug in every bearing kit to block the unused passage.

A sealed Perma‑Lube bearing is superior because it needs no external seal, offers far less chance of water intrusion, and eliminates the periodic greasing required by older greaseable designs.


A01 vs A02: The Difference Between These Part Numbers

Both 30‑879194A01 and 30‑879194A02 share the same core features: permanently sealed construction, self‑aligning design, identical outer dimensions, and the included plug for older transoms with grease fittings.

The only functional difference is the thickness of the inner bearing race

30-879194A01 (Quicksilver)

  • A01 uses a reduced inner‑race thickness (about .090" removed) to provide additional clearance for specific U‑joint designs.

30-879194A02 (Quicksilver)

  • A02 uses the original full‑thickness inner race for drive families that do not require the reduced‑thickness design.

Mercury’s Catalog Recommendation

Alpha One Drives

• 1997 and earlier (Serial: 0K999999 and below) → 30‑879194A02

• 1998 and newer (Serial: 0L100040 and up) → 30‑879194A01

Bravo One, Two, and Three Drives

• 1995 and earlier (Serial: 0F729999 and below) → 30‑879194A02

• 1996 and newer (Serial: 0F730000 and up) → 30‑879194A01

Note: Bravo X or XR drives must use bearing 30‑879194A01 or interference will occur between the U‑Joint and the bearing causing the U‑joint, the bearing, or both to fail.

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Laura California https://SmartBoatParts.com