I believe that precaution only applies to the kit type trailers coming in from southeast Asia. The story goes that they ship with an inferior moisture repellent grease that doesn't hold up as a high speed wheel bearing grease. Apparently it says right in the literature that the bearings need to be cleaned and properly greased prior to being placed into service. (To me this makes no sense whatsoever that they assemble the hubs with the seals, only to turn around and give instructions for the customer to disassemble them, which 9 times out of 10 means you need to put new seals in!)
On your Flexride I would not worry about it. For peace of mind, if you pull a dust cover off and can see grease, you are almost assuredly okay. If you are unfamiliar with the process, you could do more harm than good. Just saying.
If you do decide to repack, it is always a good idea to put new seals in; they can be damaged, regardless of the tricks used to pull them, so have a set on hand before starting.
Some people like to put more grease in than the typical production line pack, others feel that just enough is just right. The key thing is not to over or under tighten the castle nut. You want it to be snugged up to the point where there is no "wink" (i.e. no clack, lost motion or free play when you push straight/pull straight/try to cock the hub) but not over tightened. There are a lot of different versions of how to achieve this, but what I generally do is push the hub on all the way by hand; push the outer bearing up firm into the cup, making sure that it hasn't slid down; put the washer on and spin the nut on by hand firmly; give it one or two wrench flats of a turn with a wrench (more if the hub was not really seated onto the bearing and you still feel wink), just to the point that all wink has been removed but not to the point that you feel any binding while rotating the hub; and then back off that same one or two wrench flats to get alignment of the cotter pin (or tab washer). Only back off the nut enough to engage the pin. A very small perception of wink in the final setting (I'm talking the merest perception) is okay, but you don't want slop; no clunking, but a little tick if any. This is a good reference point for small trailer axles and your typical passenger car.
By comparison, on the 7klb axles we are putting under our new punkin chunkin trailer I had to pull a hub to confirm which was the leading brake shoe. The factory nut setting on that was just a little snugger than finger tight, so when I reinstalled it I went right back to the same spot on the castle nut. There was not a lot of excess grease in the outer bearing, but it was well packed with good quality grease, so I didn't bother repacking.
The Timken technical 'white paper' report on bearing setting techniques can be found
here (linky). It basically says the same thing for hand setting, but hymns and haws a bunch about all of the factors that make doing this by feel an inexact method.
by nelsonrx » Wed Sep 21, 2016 10:25 am 
