Replace your damaged or missing grease caps. Make sure to check out the Diagrams at the end on the video showing the measurments of typical grease caps and the hub inner diameter they fit. Grease Caps are designed to be slightly larger then the hubs so they have a tight fit.

1.98" Grease Caps Available Here: (Most 3.5k Axles 5 Lug)
https://www.amazon.com/PosiLubeGrea...

2.44" Greae Caps Available Here: (Most 5.2k Axles 6 Lug)
https://www.amazon.com/PosiLubeGrea...

2.717" Grease Caps Available Here: (Most 7k Axles 8 Lug)
https://www.amazon.com/PosiLubeGrea...

https://www.johnsontrailerparts.com/
IG: @johnsontrailerparts