Greasing Trailer Wheels

ah64id wrote:

Bill & Kate wrote:

ah64id wrote:
The cavity does NOT have to be full to get grease to transfer to the outer wheel bearing, the internal shape of the hub allows grease to travel.

I am afraid that is a misleading statement. On both the Dexter EZ-Lube as well as the similar AL-Ko Ultra Lube hubs, the grease must enter through the grease fitting, and pass through a hole drilled down the center of the axle to the area between the inboard seal and the inboard bearing. From there it is forced outward through the inboard bearing into the space between the inboard and outboard bearings. Once that space is filled up, the grease continues to be forced outward into and through the outboard being and escapes out through the space around the outside of the outboard bearing. The first time the grease fitting is used after hand packing and installing the bearings, enough grease must be pumped in to completely fill that space before any grease will be forced into the outboard bearing. The first grease forced in will be the "dirty" grease that has just been forced out of the inboard bearing, so that is why it is important to pump until you see "fresh" grease. Depending on how big the axle is, this can take most of a big cartridge of grease per each hub. Once the space is initially full, much less is required ....

If your goal is to force grease with the gun to the outer bearing then yes that might be true, but the design of the hub WILL sling grease from the inner to the outer without the cavity being full.

I just had mine apart tues and wed this week, my cavities where NOT full and grease was definitely moving around from the grease rifle to the outer bearing. This is all based on the design of the hub between the bearings. As the grease gets warm it moves the excess grease towards the outer bearing.

Bill & Kate wrote:
At any rate, everything should be taken apart, inspected, hand packed, and installed with new seals every 10,000 miles or couple of three years regardless of how much you pump in between inspections.

Absoloutly, the old grease isn't removed with just pumping new grease in.
Wheel bearings on vehicles where never able to be greased like this, they just took standard maintenance. The design of the hub was also different, it didn't have the machined taper.

"Slinging grease" from the inner thru the outer bearing... Now that's a new thought, (for me at least) had never heard that before... I find these wheel bearing threads fascinating reading..I've read about "churning", where the bearing is so full of grease that the rollers will slide instead of rolling in the race... if the center section of the hub is full of grease, it can't help transfer heat to the wheel and away from the bearings... etc. etc. Guess you pay your fifty cents and state your preference... hear's mine, tear apart, wash with lacqure thinner, hand pack with synthetic grease every two yrs... unless one wheel feels hotter at a reststop than the rest of them. Travel safe :)