Grease or Oil Bath Hubs For a Boat Trailer

Updated 08/18/2014 | Published 08/16/2014

Question:

I would like to know if the water settles to the bottom as oil usually floats on water, which would cause the bearings to rust anyway. I had huge problems with my tri-axle trailer using bearing buddies and had to replace the bearings each year at a huge cost. What I did was drill a rubber truck plug into the cap, then drilled and tapped a hole into the centre of the cast iron housing, between the 2 sets of bearings. I put a grease plug in the hole. After a couple launches I remove the cap and pump grease in the cast housing and usually water will come out. I havent had a problem with bearings even though I put inexpensive Chinese bearings in, for over 10 years now. This is great but messy. If the water mixes with the synthetic oil or floats on top so it may be drained out, not damaging the bearings while it sits, I will convert to your style of bearing protection. I have been told by my trailer manufacturer that oil bath systems dont work on boat trailers without leakage because of total submersion into water. What is the failure rate?

asked by: David F

Helpful Expert Reply:

If your current setup is working well I would recommend you stick with grease hubs. Oil-bath hubs are normally used on heavier duty style trailer axles. They must also be closely watched in situations where the trailer is submerged in water, because the oil will breakdown much faster than grease will when water is introduced. Standard grease filled axles are a better choice because they can be maintained easier.

The other problem is that when a seal goes out in a grease hub you can make it home typically to replace the seal without damaging the bearings or hub, whereas with a oil-bath system once you lose a seal all of the lubrication disappears and you have to park the trailer till you get the correct replacement parts.

expert reply by: Jameson C