I agree with those that say using the zerk fitting is a no no. The old grease doesn't just disappear like a fart in the wind. It stays in the bearing/hub, and breaks down over time. Given what I've seen in personal experience, once every year or two of towing would be a good timeline to repack/inspect bearings unless you are putting a lot of miles on your camper. If you pump more grease in, something has to go somewhere...you'll either blow the dust seal, or squeeze it out where it should not belong. The most important factor to proper bearing/lube life is proper torque load on the bearing, and not over-greasing - more is not always better. If you remove the bearing, clean it out and the hub, and re-pack and lube you are so much better off than to just use the zerk. The zerk has it's place in industrial equipment - mainly on assembly lines where tearing down a machine to replace a bearing is not cost effective, so you just pump more grease into a zerk and go on your way. When the bearing begins to fail, then you do a tear down. Just my two cents...and I do heavy
maintenance for a living!!!
Mark, Brooke, Keira, and Gunther the Pup.
2013 Salem Cruise Lite
2003 Ford SD Diesel