Sorta like bearing buddies, but where they just put a positive pressure on the grease via a spring to keep water out, these other doohickies actually just push old wet grease out from the back toward the front as you pump, pushing the nasty wet grease out when you do your bearing maintenance. Once a year, or whenever...you just pump in fresh grease, and any old or contaminated grease is pushed forward, and out, and when fresh clean grease is exposed, you wipe away the contaminated stuff and you are done. You have to pull the rubber plug out, and the grease zerk is exposed underneath. Pump the new grease in, and when it comes out clean, stop, put the rubber plug back one, and tow it away for a year or so.
That happen to me on a few occassions w/ my Bass Tracker boat trailer. I finally figured it out - just insert enough grease in to keep things lubricated. I learned my lesson after replacing a few seals. I had the same type of hubs in the 1st pix of the previous post...
not everyone will agree but you can...over grease...a bearing. when this happens the roller bearings slide instead of rolls...
X2! The bearings should be packed and a thin film of grease goes on the spindle and inside of the dust cap to prevent rust. If the entire area inside the hub is filled with grease, it will actually create drag!
This one is designed to be filled with grease. There is a hole in the spindle just to the inside of the inner bearing, between it and the seal. As you pump in the grease zerk, it forces the old grease forward toward the zerk, completely filling the space. You keep pumping until clean grease comes out on you, then put the rubber cap on them. My trailer came with these, but like a couple of you said, I don't fill my void. I converted to regular setup with a metal cap. I like to take the bearings out yearly and actually clean them off and inspect them, rather than just keep shoving grease on them.
back in the day...I was shop foreman for...Evridge/Scorpion trailers... I have seen several different "low" maintenance hub assys. the best way I saw to keep water out of the bearings was...when you get to the lake...let the hubs cool all the way down before you back into the water. also if you unplug the trailer lights, they have less chance of blowing a bulb from it being hot from the brake lights being on as you back down the ramp and submersing them under water... note...don't believe that the ball grounds the trailer lights...wire in the ground wire on the vehicle side of the plug. the ball should be greased... trailers 101...:Handshake
