How to Properly Grease a Bearing Buddy Hub (Boat & Utility Trailers)

A Bearing Buddy is a spring-loaded grease cap designed to keep water and air from entering the hub—especially helpful for boat trailers. Here’s how to grease it correctly:

Steps to Grease a Bearing Buddy Hub

1. Remove the Bearing Buddy cap.
   Pry it off gently using a flat tool, working around evenly to avoid damage.
2. Check piston movement (grease level).
   Press the edge of the internal spring-loaded piston or blue ring. If it moves or rocks, the hub is properly filled. If not, it’s time to add grease.
3. Fill with marine-grade grease.
   Attach a grease gun to the Bearing Buddy’s grease fitting. Slowly pump grease until the piston extends about 1/8″ beyond the cap’s front.
4. Check pressure relief.
   If grease leaks around the piston edge, that’s the automatic pressure relief in action—indicating sufficient fill.
5. Confirm piston movement.
   With the grease gun still attached, press the hose lightly against the piston. If the piston moves inward under pressure, it’s not full; add more until it resists movement and returns outward.
6. Bleed trapped air.
   Drive a few miles to help air escape from the hub. You may need to add a little more grease to bring the piston back to 1/8″ outward.

Which System Is More Work?

Bearing Buddy hubs demand more manual labor over time due to the need for full repacking and inspection, especially after water exposure. Super Lube hubs offer simpler routine maintenance with grease purging and quick inspection—less overall work and more efficient.

Bearing Buddy vs. Super Lube (EZ Lube) Hubs: Comparison Guide