Servicing Trailer Bearings

Step by step instructions

Safely jacking up the trailer

1. Park the trailer on firm and level ground.
2. Block the trailer tires on the opposite side securely so that no forward or rearward movement is possible.
3. Jack up the trailer following the manufacturer's instructions.
4. Secure the trailer on jack stands of adequate capacity front and rear.

Remove the wheel and hub

1. Undo the wheel nuts and remove the wheel.
2. Pry off the dust cap using a flat bladed screwdriver.
3. Straighten out the cotter pin that holds the bearing nut and remove it.
4. Remove the bearing nut and washer.
5. Gently pull the brake drum forward while cupping the hub opening with your hand to keep the front bearing from falling to the ground. The outer race stays in the drum, while the inner race and roller bearings come out as an assembled unit.
6. Place the front bearing, bearing nut and the bearing washer in a clean container.

Remove the grease seal and inner bearing

1. Place the brake drum face down so that the back of the drum is accessible.
2. Pry out the grease seal. This will be replaced in a further step.
3. Lift out the rear bearing and place it in the container with the rest of the parts.
4. Don't mix up the bearings if you are doing more than one wheel at a time - each bearing must mate with its original race (no prejudice intended). The bearings wear in by a certain amount and need to be matched with their respective counterparts.

Clean and inspect the bearings and races

1. Thoroughly clean the bearings and other parts in a solvent (not gasoline!) until all the old grease is removed. Set them aside to dry completely or blow dry with compressed air. Don't use the air pressure to spin the bearing, as damage could result to the bearing or to your person!
2. Clean the hub and spindle.
3. Inspect the bearing races for heat discoloration, pitting, scoring and any unevenness.
4. Inspect the bearing for damage as above. Any out of round rollers, cracked roller cages and rough running will indicate replacement is required.
5. The bearing and both inner and outer races must be replaced as a set.
6. Inspect the brake drum for pitting and excessive wear especially if the brake shoes were allowed to wear down to bare metal.
7. Inspect the brake magnet surface for excessive or uneven wear.
8. If the brake drum and magnet have been saturated with grease from a failed seal, replace the shoes and magnet, and have the drum turned or machined to renew the surfaces.

Hand packing the bearings

1. Place a walnut sized gob of wheel bearing grease in one palm.
2. Grasp the bearing with the other hand so that the wider end is facing the grease.
3. What you want to do is force the grease into the gap between the inner race and the outer cage so that it squeezes up through the rollers and out the top.
4. Press the bearing down into the grease in a rocking motion and continue until the grease oozes up.
5. Rotate the bearing 1/4 turn, at a time, and continue until the bearing is completely filled with grease.
6. Or use an inexpensive bearing packer - there are some that you use with a grease gun filled with wheel bearing grease and other types that you drop the bearing into and apply hand or foot pressure to force the grease through the bearing.

Bearing packers at Amazon