Buddy Bearings work by maintaining a constant, slight positive pressure inside your axle's wheel hub, preventing water, dirt, and other contaminants from entering and damaging the wheel bearings. This clever design ensures the grease-filled hub remains sealed and the bearings are continuously lubricated and protected.
The Core Mechanism: Maintaining Positive Pressure
The fundamental principle behind Bearing Buddies is the creation and maintenance of a slight internal pressure within the wheel hub. This is achieved through a spring-loaded piston system.
Here's a step-by-step breakdown of how they operate:
- Grease Filling: The axle hub is filled with grease through a Zerk fitting (grease nipple) on the Bearing Buddy. As grease is pumped in, it builds up pressure inside the hub.
- Piston Extension: This increasing grease pressure forces the spring-loaded Bearing Buddy® piston outward about 1/8 inch. This outward movement indicates the hub is adequately filled and pressurized.
- Constant Pressure: Because the piston is spring loaded, the piston exerts a slight (approximately 3 PSI) pressure against the grease. This continuous outward force from the spring ensures that a slight pressure is always maintained between the inside of the hub and the outside environment.
- Contaminant Exclusion: This constant positive pressure is crucial. If the hub cools down (e.g., when a boat trailer is submerged in cold water after a drive), the air and grease inside the hub contract. Without the Bearing Buddy's pressure, a vacuum could form, sucking in water or dirt through the rear seal. However, the 3 PSI exerted by the piston prevents this vacuum, instead pushing grease slightly outward, sealing the hub against ingress.
This continuous outward pressure effectively creates a barrier, keeping harmful elements out and ensuring the integrity of the bearing lubrication.
Key Components of a Bearing Buddy
A typical Bearing Buddy consists of a few essential parts working in unison:
- Outer Barrel (Housing): This durable metal casing replaces the dust cap on your wheel hub.
- Spring-Loaded Piston: Located inside the barrel, this piston moves in and out, applying pressure to the grease.
- Indicator Ring (Grease Level Indicator): A small ring on the piston that is visible when the piston is extended, indicating sufficient grease and pressure.
- Zerk Fitting (Grease Nipple): A fitting on the front of the unit that allows a grease gun to be connected for easy refilling.
- Internal Spring: Provides the constant force against the piston, maintaining the desired pressure.
Benefits of Using Bearing Buddies
Utilizing Bearing Buddies offers significant advantages, particularly for trailers that are frequently exposed to water, like boat trailers:
- Prevents Water and Dirt Contamination: This is their primary function, safeguarding bearings from corrosive elements.
- Extends Bearing Life: By keeping bearings properly lubricated and free from contaminants, their operational lifespan is dramatically increased.
- Reduces Maintenance: Less frequent bearing replacement and packing are needed, saving time and money.
- Simple Grease Check: The visible piston extension (1/8 inch) provides an easy visual indicator that the hub is sufficiently greased and pressurized.
- Easy Lubrication: Re-greasing is a quick and clean process via the Zerk fitting, without the need to disassemble the hub.
Practical Application and Maintenance
Installing Bearing Buddies is straightforward, often replacing existing dust caps. Maintaining them is equally simple:
- Initial Filling: Pump grease into the Zerk fitting until the piston extends about 1/8 inch, as described above.
- Visual Check: Periodically check the piston indicator. If it's no longer extended, it's time to add more grease.
- Regular Greasing: Top off the grease as needed, especially before long trips or after submerging a trailer in water.
By understanding how the spring-loaded piston maintains constant positive pressure, it becomes clear why Bearing Buddies are an invaluable accessory for protecting trailer wheel bearings, especially in harsh conditions.
