Can't trust the axle manufacturer, TT manufacturer or dealer on this stuff that it was ever done right.
First TT we owned wouldn't brake properly from day one. Dealer kept blaming our brake controller, but a new one made no change. After a year of arguing with the dealer, days before the warranty expired they took it all apart and found blown seals and grease on the brakes. Do not know if the dealer had pumped in grease.
{Our 2nd TT got taken back under warranty after finding major frame issues on 2nd day of ownership.}
Now on our 3rd TT, we took it to the dealer for some warranty work after the first season of use (has a 2 year warranty). Asked them to please remove the drums and inspect brakes and seals. They said all 4 seals were blown and they wanted $1K to repair it. WTF? I phoned Al/Ko and they said it would get fixed under warranty and that they would talk to the dealer. I also phoned the dealer, told them what Al/Ko said and they said they would take care of it. At end of 2nd season, I found one bearing was running much warmer than the others. I took the drums off to find that there was insufficient grease and not only that, there was two colors of grease meaning that the dealer never replaced the seals at all. Total BS lie on needing new seals (fraudulent actually). I also found that the nuts were over-tightened - not good. During PDI, the dealer had pumped in a couple of squirts of grease and called it good. I installed all new Timken bearings and for past 2 seasons, zero issues. If the seals & bearings had been left alone from the beginning, we could have had a failure anywhere, at any time while on a trip.
I'm of the opinion that the grease zerks are a bad idea. Inspecting even a new trailer is a good idea. It's so easy to pull a drum off to inspect both the brakes and seals/bearings, why not do it once a year or may two depending on mileage. Not all Ch*nese bearings are going to fail, but enough of them do that I'd rather have top quality ones. Some say US-made Timken bearings are hard to find but I had no trouble getting them locally. I carry one spare set along with some grease.
After 3 TTs in just 3 seasons and so many other problems in addition to above, I've become a hardened and cynical RV owner. :R