Buddy bearings tend to be used more on boat trailers but are still good for any trailer. Boats have a habit of getting water contamination when hot wheel bearings are immersed in cold water, it creates a vacuum and sucks in water. The buddy bearing helps get some fresh grease in there and displaces the water. It tends to be the smaller outboard bearings that will get dry and show heat first. It's really simple to grease bearings but it's heavy work for a novice and you'll definitely need to get your hands dirty.
Here's the process to pack wheel bearings... you can decide if you want to tackle it as a project or pay a mechanic. Start by safely jacking the vehicle and place securely on a jack stand. Once the wheel is clear from the ground, I check for wheel bearing play by gripping the tire at 12 and 6 o'clock and giving it a good push pull. I also check at 9 and 3 o'clock. Any detectable movement or clunk clunk means the bearings are dry and loose; no noise or play means all is well. I'll also spin the tire to check for dry bearing noises or brake drag. After removing the wheel, next remove the dust cap from the spindle, it's typically a press fit. I use large channel lock pliers, a hammer, or vice grip depending on dust cap size and how tight it is. Under the cap you'll see a greasy castle nut with a cotter pin holding things in place. Remove the cotter pin and the castle, then use a large wrench to unscrew the spindle nut. There is typically a large washer under the nut holding the outboard bearing in place. Once the washer is off, the whole hub with bearings and seal and all should slide right off. I say should because brake hubs might bind on the brake shoes if excessively worn or misadjusted. Once you have it apart it will become plainly obvious how everything fits together. After that you pry the seal out, clean the grease with paper towels and solvent, and thoroughly inspect the bearings. Good bearings have very little discoloration and the rollers should have a nice even sheen. Any scoring, pits, rust, black spots, brown or blueing means heat or corrosion damage and the bearings should be replaced. Also inspect the bearing races in the hubs. Damaged bearings and races are replaced in matched sets. The races are press fit in the hub so that's a project in itself. You beat them out with a big hammer and chisel, and press new races back in place. Bearings need to be packed with grease. Packing a bearing means there is solid grease and no air voids or bubbles in the bearing. Shops have a special tool to grease bearings; if doing it at home there's a trick using a blob of grease in the palm of you hand and swipe the edge of the bearing to force the grease into the shell and across the rollers. I can't really describe how to do this because you have to hold everything just right to get it to work. I learned by watching my grandfather do it. You will also need to inspect the spindle where the bearing sit, and the seal surface for any damage. Once cleaned, inspected, and greased, you reassemble everything using a new seal. Wipe a thin film of grease on the lip of the seal and spindle where the seal rides so the seal doesn't start dry. Torque on the spindle nut is critical. Start by overtighting the nut and roll the hub back and forth to check for any binds. This also helps to seat any bearing races that were off a bit. Back the nut to loose and set the bearing preload. Bearings like to be a bit loose rather than too tight. The metal grows in size with heat, to too tight will kill the deal. Setting the preload is more by feel or intuition. I go full loose on the nut and using a 12" crescent wrench at 1 o'clock I let the handle of the wrench fall on it's own weight. Then I test fit the castle lock. Rotate the castle around to find the place where the cotter will go in and hold the nut from backing off. Install and bend the cotter, making sure it won't rub on the inside of the dust cap. Hammer on the dust cap, install the wheel and you're in business.
Itripper Thanks for posting those links! When I say " The only links I can do are the kind ya cook....I Ain't kidding!
