Actually very easy if you can find parts, I could not and ended up switching to greace nipple type..

To get caps off, use a rubber mallet at tap around the cap, trying to hit the cap away from centre and or kinda grab and pull the cap off.. Likely o rings inside are dried, cracked or torn, maybe even just try retapping the cap on, use a board in front, to avoid cracking if you go this route. It worked for a season for me but then I got tired of cleaning the wheel and topping up oil.

Eventually I found new grease nipple bearing set up from a dealer and I use high temp water resistant marine grease. So far so good.. Was actually quite a simple job as my actual bearings were in good shape so Drained, wiped clean, installed grease nipples , filled. Drove trailer a little topped up and put dust covers on.. Initial fill you need to overfill bearings to get grease in the whole cavity, then after that just top up do not overfill.


I had a service guy basically explain procedure surely your local dealer can do the same, hope this helps.. Btw the vault system that replaced oil bath is being phased out so I did not go that route.. Talked to someone at a trailer shop afterwards, and they said they would have gone the same route.