Deceided to check my wheel bearings today and never have seen this before. What type of bearing cap is this? and how do you mainyain them? The little center button is rubber and can be pressed in. I've had buddy bearings, oil bath hubs, but never this???? looks like the previous owner chewed it up trying to remove it.

i would change it out with a bearing buddy don't know what type that is but looks like you might have problems since it looks like you can't grease it

Found out what it is! It is a very popular type bearing down along the coast. You greese it thru a greese zert in back of the hub, by doing so it pushes the greese thru the bearings from the back to the front, you know when it's full when the greese pops out the center rubber plunger, this way its almost impossible to blow out the rear seal~~whoever tried to remove it at some time tried without taking the wheel and tire off and put a small crack in it, a complete replacement set is a whole 7 bucks!

i was really shocked to see that when i pulled the cap off there is also a greese zert in the end of the axel shaft, i just put my greese gun on it and started pumping, the greese was thinner than it should be and gray which means water has been getting in, as i pumped greese in it pushed out all the old greese till the new white greese started comming out. Kinda unique system.

My Nitro boat trailer has those. Inspect all your rubber plugs. I had a couple that had cracks in them right in the center hub part (bacically the zerk cup). The zerks are drilled off center and I guess they can rub on the plug.

on both mine, the previous owner must have tried to take them off with channel-locks and bent them up, they came off the old way, screwdriver and hammer~~I ordered 2 new ones. both my rear greese zerts are pluged, I'm guessing they are a standerd sized zert, taking them out today and try to find new ones, i like the option of greesing from the rear without taking the wheel off.

Yea, that greese cert under the rubber cap is where you greese it. The greese runs through the spendle and into the back of the bearings, thus, pushing old greese forward. I pump greese until I have clean new greese coming out the front. On my trailer, there is no cert in the back. Just the center one.

Hope this helps.

I don't see why we cant just go back with buddy bearings? pushing greese in from the back should still press the buddy bearing.