Wheel/Brake/Bearing Question

I spent my entire career in the bearing business. 40 years; Including teaching proper bearing handling/maintenance. Most bearing failures are the result of poor maintenance that includes overgreasing, improper mounting, and contamination caused by improper installation. Do "not" preload your trailer bearings. Follow the procedure from Dexter as posted above. Preload will cause overheating which leads to premature wear and grease failure which leads to bearing failure. Also, pumping in all that grease just fills the cavity and could blow the seal. That extra grease does nothing but make a mess. If you notice, every instruction tells you to simply pack the bearing well with the proper grade of grease. That's all that is needed to provide thousands of miles of service. The bearing actually purges the excess grease in the first few moments of operation. Boat trailers recommend filling the cavity to help keep water out. When the boat trailer wheels are submersed into the water, the temperature change can pull water into the hub cavity, so the extra grease is there to protect from this water intrusion. Other trailers should never see wheels under water, so all that extra grease is needless. You will never have a bearing problem if the "manufacturers" guidelines are followed. Any other advice can be harmful. I would see this in many maintenance training classes where people would tell me "I've been doing it this way for years (the wrong way)and never had a problem".. It was interesting that those were the customers who spent the most on bearing and machine maintenance. Bottom line - proper amount of grease, new seals, clean hands, clean work area, clean spindle, clean hub, proper running clearance (no preload) = no problems.