Bearing buddy issues

[ratdude747]

I've been having a few issues with my trailer's bearing buddies (genuine chrome plated) that I installed last spring when I added electric drum brakes to my trailer.

1. The "bra" covers pop off when in use. My assumption is that this is due to brake drum heating which is expanding the air inside the buddy. I've confirmed this by driving with them off, then putting them on when parked or ramp dipping and observing them sucked in as the wheel cools off. Is driving with them off the correct solution?
2. When I pulled my boat out of the water at the end of yesterday's outing, the grease nipple was missing and not in the bra of one of the two units. Thankfully, it was pushing grease out (not sucking it in). Are the nipples replaceable or do I need a new unit? I suspect it fell off when I was towing the boat 1 hour from home to the ramp. I don't recall losing a nipple while topping them off during the offseason.

 

[alldodge]

I'm wondering if the hubs are getting hot, normally the covers don't come off unless pulled off. Do you have a IR temp gun to measure temps.

Could drip a drop or two of water or spit on the hub after a run and before launching boat to see if it sizzles

 

[airshot]

My rubber caps used to come off on ocassion, so I started making a teeny tiny hole with a paper clip right in the middle. When I install them I push on the center to create a little suction on the rubber cap, enough so the center will suck in slightly. I often wondered if heat buildup caused the " bra's" to come off as the center would be bulged out after a trip. With the pinhole, there is no bulging and have not lost another " bra"... Do check your hubs for excess heat. If to hot for your hand to remain on them, you have another issue....warm is fine but never hot !

 

[Mc Tool]

I thought the idea was to remove all the air . I have rubber ones and they do move in and out about ⅜" between start and finish of the trip but not close to popping off

 

[dingbat]

There should be no pressure on the bra.

If you’re popping the bra, the bra is sun damaged and needs replaced or the o-ring on the piston assembly is compromised.

A missing grease fitting would cause the problem as well

 

[Jeff J]

No reason to think a little heat from the sun or heat buildup from being on the road wouldn’t expand the air trapped under the cap and push them out. I had some caps that would push out just from the little bit of compressed air created while pushing them on. The pinhole idea is a good one.

 

[ratdude747]

No reason to think a little heat from the sun or heat buildup from being on the road wouldn’t expand the air trapped under the cap and push them out. I had some caps that would push out just from the little bit of compressed air created while pushing them on. The pinhole idea is a good one.

I know for a fact that happens. Putting the bra covers on warm (not hot!) bearing buddies at the ramp then dipping the trailer at the ramp causes the bra to get pulled in very far. Thus, even with no cover, the heat coming from the hub is enough to warm the air inside the opening of the bearing buddy to the point that it contracts when cooled.

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I can confirm the bearings aren't getting super hot. Just some heat from the brakes doing what brakes do. Nothing to suggest bearing failure. Obviously warmer than a brakeless axle...

As for the grease nipple issue in my original post: is this serviceable or do I need to replace the bearing buddy?

The bras are not obviously sun damaged.

 

[MikeSchinlaub]

By bra, we're talking about the plastic cap right, I find those around our lot all the time, they constantly fall off.

As for the grease fitting, I don't see why you couldn't replace it. They all just thread in right?

 

[Chris1956]

Brakes generate heat. That is their function. Heat expands the grease. That is why automobiles do not have bearing buddies on them.

Try putting less grease on the bearings. Pack 'em as you would a car/truck cone bearing.