Jack up the trailer and support the frame or axles with jack stands. Remove the wheel and then the hub dust cap with slip-joint pliers. Unbend the cotter pin, grab the head with side cutters and leverage it out of the castle nut. Spin the nut off with pliers. Then pull the hub forward until the washer and outer bearing fall into your hand.
Spoon a glop of new grease into the palm of your hand. Then slap the edge of the bearing into the grease. Force the grease into the bearing cage like you're scooping dip with a potato chip. Rotate the bearing and repeat until the bearing cage is filled with grease. Smear the rest of the grease over the face of the bearing rollers.
Clean all the old grease out of the hub. Then wipe fresh grease on the inner race and set the bearing in place. Position the new grease seal with the open edge of the lip facing in toward the bearing. Place a flat steel plate or wood block over the seal and smack it into position until the seal is fully seated. Then wipe a light coat of grease around the inside of the new seal.
Remove the old grease from the axle. Slide on the hub, outer bearing, washer and castle nut. Tighten the castle nut until it's snug. Spin the hub to spread the grease and seat the bearings. Resnug the castle nut, then back it off a quarter turn to line it up with the hole in the axle. Insert a new cotter key and bend the ears. Tap in the dust cap.
You know you’re supposed to repack the wheel bearings on your boat, horse or utility trailer. But do you? Well, not as often as you should, according to Field Editor George Andriotis, who owns D&G Auto and Trailers in Bridgeport, CT. George routinely gets calls from stranded trailer owners. The No. 1 cause? Fried wheel bearings.
You can avoid being stranded by repacking your wheel bearings on a regular schedule. If you use your work or utility trailer daily or drive it long distances, repack them every six months. Repack annually if it gets occasional use and/or the trips are short. For boat trailers, repack the wheel bearings at the start and end of the boating season. Use marine wheel bearing grease.
Repacking wheel bearings is cheap (less than $15) and you can do it yourself in a few hours. Pick up new grease seals, cotter pins and the wheel bearing grease at any trailer supply shop. Grease seals come in various sizes based on the inside dimension of your wheel bearings. So after you pull off the bearings (Photo 1), take them to the store to match them with new ones. You’ll also need a seal puller (Grip No. 22180 Seal Puller; $7 from amazon.com) degreaser solution, parts cleaning brush, washing tub, slip-joint pliers, side cutters, floor jack and jack stands. Then follow the simple photo series.