Trailer wheel bearing question

[Rich Jones]

Okay, now that I'm moving away from the ocean to the fresh water lakes of Vermont, do I have to worry about the grease in my wheel bearings? Is it just salt water that screws them up or water in general? I've put "bearing buddies" on two of my trailers, but some people say there's the danger of too much pressure on the rear seals. What say ye? Thanks.

[David G]

I put bearing buddies on an ancient trailer once, and blew out the real seal on one side. It was a seal that, unfortunately, was irreplaceable. So, now, it leaks a bit of grease. Eventually I'll replace the whole shebang, but it's not too bad now.

It's all water, though the salt water is certainly more corrosive. I'd still do the bearing buddies. Or, if you want to go upscale, do the oil-bath types.

[Woxbox]

Fresh water will screw up the bearings plenty fast. The only mistake people make with Bearing Buddies is putting too much grease in them. Follow the directions and they work great. (Just enough grease so that the plunger moves when the wheel is cold and you push on it.) Any more, and the seal is liable to go when the whole shebang gets hot and expands. I learned this the hard way, but got good and replacing seals and repacking hubs as a result.

[Canoeyawl]

There are different types of "bearing buddies" - the original brand name type have a pressure relief port, you can't over pressure them. There are other types that pressure through the center of the spindle. If those are used on a non-drilled spindle you can push out the seal.

[JuniperHeartPine]

At the risk of getting banned,

http://www.youtube.com/watch?v=2OpuuAa7gdE

[Gold Rock]

Woxbox said it just right (with particular regard to the spring loaded diaphram; just enough grease to move the diaphram and that's good...). BB and their clones are just moisture displacement devices. Fill the entire hub cavity with grease and no moisture can enter. Fresh water will do in spindles, hubs, races, and bearings in just like salt, if perhaps less quickly. Keep the water out and you're fine.

[Canoeyawl]

The reason "Bearing Buddies" work on boat trailers is that when the trailer is on the road the hubs and bearings (and the grease) warms up and expands. The spring loaded diaphram will allow this.
Now, when you submerge those warm bearings, grease, and hubs into the water it all contracts, pulling a little vacuum. If there is no positive pressure ( the loaded spring) water will be drawn in through the seal (they only really seal in one direction, the wrong one for this application) and after a few trips to the lake you will have water in the hubs.
It's basic physics, expansion and contraction.
I "load" the springs in the bearing buddies with a grease gun every time I take out the boat.

[Rich Jones]

Thanks, all. The advice sets my mind at peace about the bearing buddies.

[Woxbox]

I "load" the springs in the bearing buddies with a grease gun every time I take out the boat.

I agree 100% with your description what goes on with the bearings, but I can't understand why you would see a need to keep adding grease. Where's it all going? Once you have the right amount in the bearings, it should be good for a full season at the very least. The bearings heat up, the plunger moves out. The bearings cool off, the plunger goes back in. But it's back where it was at the beginning of the day, no more nor less in my experience.

[Tom Lathrop]

My latest trailer has a new kind of cap. It has a rubber diaphragm which seems to act much like a BB spring. Appears to work just fine. No grease fitting though.

[Canoeyawl]

I agree 100% with your description what goes on with the bearings, but I can't understand why you would see a need to keep adding grease. Where's it all going? Once you have the right amount in the bearings, it should be good for a full season at the very least. The bearings heat up, the plunger moves out. The bearings cool off, the plunger goes back in. But it's back where it was at the beginning of the day, no more nor less in my experience.

It is just the air that leaks out over time I guess. I don't bother to fill them full the first time, no need as long as there is a positive pressure. Just pack the bearings, slap a handful of grease(straight moly grease, no "boat trailer grease") inside the hub and put it together. I use the same grease gun for everything.
I haven't replaced a bearing in over 10 years, but I do a cursory inspection for water every couple of years.

[Breakaway]

http://forum.woodenboat.com/images/misc/quote_icon.png Originally Posted by Woxbox http://forum.woodenboat.com/images/buttons/viewpost-right.png (http://forum.woodenboat.com/showthread.php?p=3016184#post3016184)
I agree 100% with your description what goes on with the bearings, but I can't understand why you would see a need to keep adding grease. Where's it all going? Once you have the right amount in the bearings, it should be good for a full season at the very least. The bearings heat up, the plunger moves out. The bearings cool off, the plunger goes back in. But it's back where it was at the beginning of the day, no more nor less in my experience

Well, when its hot, the grease compresses more easily, gets oily and drips out--not sos youd notice it...but it does go away. Also, there are some trailers, like the EZ Loadr I own, that have a "through spindle" lube system. The grease gets forced through holes in the spindle to evenly spread around front and back bearings. Excess actually squeezes right out the center of the spindle on the backside.

The theory is that every time you add grease, you force out the old grease, extending the time between servicing the hub by taking it all apart, cleaning it and repacking and reassembling.

This works well, But dont use bearing buddies if your trailer has "spindle lube" since the spring pressure just pushes the grease right out, Instead, you use a grease cap with a zerk fitting.

I have an EZ Loader, but Champion trailers and others have similar systems. Here's a pic I grabbed from Champion's website.

http://www.championtrailers.com/images/cuthub.gifhttp://www.championtrailers.com/images/spdl.gif