Bearing Protectors vs. Posi-Lube Caps vs. Standard Dust Caps

There are 3 types of “caps” for your hubs; bearing protectors, posi-lube caps, and standard dust caps. Here are the features of each to help you choose what is best for your situation.

Bearing Protectors

Even with a newly or “perfectly” lubricated hub, friction causes the hubs to become hot. With all trailers, this can cause major issues. For boat trailers, the rapid change in temperature from hot to cool during launching and loading of your boat causes a suction that draws water and debris into the hub where it will corrode your bearings and potentially cause irreparable damage to the entire hub. There is a similar issue with other types of trailers, but mainly with the ones that are rarely used. When a trailer sits unused, moisture that has built up during the “cool down” period, sits inside the hubs causing rust and pitting.

When grease is pumped into the bearing protector using a grease gun, the spring-loaded piston will move outward to indicate when to stop filling. Due to the constant pressure provided by this piston feature, there is nowhere for water and debris to go when the hubs are submerged, ensuring a longer bearing life.

Before using bearing protectors for the first time, we suggest that you do a complete inspection of your hubs and all of its components. You will want to remove the hubs and check both bearings, races, and seals. You will want to look for pitting, rust, or anything that look suspicious. Check the seals for dry-rot. If you are unsure, it is best to simply replace the seals. Clean the hubs and all components of all the old grease.
Bearing Protector

When purchasing bearing protectors, it is suggested that you also purchase a cover. The cover slips over the protector and keeps any grease that is expelled from the protector during from getting all over your tires, wheels, or trailer.

Posi-lube cap

Spindle with
Zerk Fitting
A posi-lube caps are the option directly between bearing protectors and standard dust caps because they have slight features of each. A posi-lube cap is used when the spindle on your axle has a zerk fitting. This fitting connects to a channel that runs from the front of the hub to the grease seal in the back. When grease is pumped into the fitting, it flows all the way from front to back ensuring the best coverage and protection. This type of spindle is the recommended option and is the only option we offer in all of our on-site custom made axles.
Posi-lube Cap
and Plug

The posi-lube cap has a removable rubber plug that when “popped”
out allows for access to the zerk fitting without having to remove
the cap each time.

Dust Cap

Standard Dust Caps

These dust caps offer basic protection, but can become quite frustrating after having to remove them each time to perform maintenance on your hubs. During removal you run the risk of denting or damaging the dust cap and having to replace them each time.

Installation and Removal

Before installation, make sure that your hub is not damaged or “welled out”. To install any of the options above, hold the cap in place by a small block of wood placed flat against the cap. Gently tap around the block of wood with a hammer in a circular motion evenly along the circumference of the cap. If you notice any issues during this process stop immediately as to not cause damage. Removal is a similar process. Take your block of wood and place it against the side of your cap or protector and gently tap the block with a hammer. Continue this process switching sides of the cap, creating a “walking” action, until the cap can be easily removed.