How much grease for wheel bearings?
I have run into this problem more then once over the years with boat and camping trailers. Over greasing zerk fitting on wheels and pushing grease through the seals and getting grease into brakes. ...
Forum Discussion
BB_TX wrote:
If you have the EZ Lube hubs, the zerk is there to purge the bearings and hub of old grease and replace it with new grease. BUT. You must do it correctly. And that means using a hand pump and pumping the grease very slowly while continuously turning the wheel. The grease is ported behind the inner bearing, then flows thru that bearing as it is turning, thru the hub, thru the outer bearing, and out the front of the hub around the zerk. That pushes all the old grease out. When you see new grease coming out the front you know all the old grease has been replaced. If you pump too hard or don't turn the wheel the pressure may push grease past the seal.
A pump or two does nothing toward getting new grease to the outer bearing. It takes a lot of grease to do it correctly.
Google ezlube for videos and how-to information if that is what you have.
Not quite correct.
Here is the facts on how this works.
The zerk feeds a hole that will attempt to grease the inner bearing. How well this will work depends on the condition of the seal/hub interface, and the skill of the person doing it.
He needs to slowly turn the wheel while steadyling pumping the grease... It is working blind as you cannot see what is really going on in there. Is the fresh grease getting evenly distributed in the bearing? Or are spots being missed/skipped? Is the seal really in good shape? or is grease seeping past it onto the brakes?
One simply cannot be sure. All seals age and leak at some point. Sometimes a brand new seal is nicked during installation... Without superman vision, one cannot know.
But the potential problems don't stop there. In order to grease the outer bearing, the grease must travel thru the inner bearing, and the hub cavity to the inside of the outer bearing. This takes a considerable amount of grease... Several tubes each time for a dual axle TT... That's right EACH TIME... The video on Dexters site is misleading. The dirty grease that they show exiting the hub is only from the outer bearing. The dirty grease from the larger inner bearing is still in there some where.... Some of it may have even made it to the inside of the outer bearing!!
Without xray vision, one cannot know exactly where it is... So one must keep pumping and pumping and pumping,, until a second section of dirty grease emerges. Even then one cannot know if all the dirty grease is purged. It is a long trip for the grease, and it probably will not travel evenly around the hub..
With all of the pumping that must be done, a compromised seal will likely fail greasing the brakes... But hey, I hear that well greased brakes never wear out.:B
So you see it is not as simple as the marketing makes it out to be.
Now knowing all of the facts, if one still wants to use this "feature" I wish them well.
