Before disassembling the bearings, preparations should be made for bearing maintenance, the vehicle should be stopped steadily and the axle should be erected to ensure the safety of maintenance operations.

(1) Remove the decorative cover and dust cover of the bearing head;

(2) Remove the tire nuts and tires, taking care not to damage the threads of the tire bolts. If it is a disc brake, the brake should be removed before using the caliper to remove the lock ring or lock pin.

(3) Use special tools to remove the bearings;

(4) Scrape off the old lubricating grease from the bearings, shaft journals, and bearing cavities, clean the bearings and shaft journals with cleaning agents, dry them with a cloth, and finally clean the bearing cavities with a cloth.

(5) Check the bearings and bearing races. If cracks, fatigue peeling, and loose bearing rollers are found, the bearings should be replaced. If any pitting is found on the bearing race, the bearing should also be replaced.

(6) Check the fit between the inner diameter of the bearing and the shaft neck, and the fit gap should not exceed 0.10mm. When measuring the shaft neck, it should be measured in the upper and lower parts of the vertical ground (which are the most worn parts). If the clearance exceeds the specified usage limit, the bearing should be replaced to restore normal clearance. It is not allowed to reduce the gap by burring or pitting on the shaft neck.

(7) After all parts meet the requirements, apply lubricating grease to the inner bearing and put it into the bearing.

(8) When applying lubricating grease to the inner cavity of the bearing, attention should be paid to squeezing the lubricating grease into the bearing until it emerges from the other side of the bearing. Apply a thin layer of lubricating grease to the bearing cavity and shaft head cover to prevent rust. Pay attention not to apply too much lubricating grease in the bearing cavity, otherwise it will affect heat dissipation and braking.

(9) Install the bearings and outer bearings back onto the shaft neck, tighten the adjusting nut on the shaft head by hand, and then use a shaft head wrench to tighten the adjusting nut to the specified torque. After tightening the nut, rotate the bearing left and right for a few turns to check the installation of the bearing; On the other hand, by rotating, the bearing is correctly matched with the race. At this point, the bearing tightness is appropriate, and the wheel rotates freely without feeling any axial clearance.

(10) Finally, install the locking plate, fixing nut, tire, dust cover, and decorative cover in sequence.

(11) After adjusting the bearings, drive for a certain distance (about 10km), stop and check to check the temperature of the bearings. If it heats up, it should be readjusted due to the bearing being adjusted too tightly, and the bearing tightness should be appropriately relaxed.

The necessity of bearing lubrication has also been confirmed by experiments and practice. When tested with a 42724 bearing at a speed of 14.3t and equivalent to 140km/h, the bearing can run for 7 hours with 5g of grease, while it can only run for 10 minutes without grease, with a difference of 42 times in lifespan; According to statistics from the vehicle department, due to poor sealing, water and sand mixed in, the lubrication of bearings is damaged, resulting in a replacement ratio of 30-60% for different types of bearings. The above situation fully demonstrates that normal lubrication conditions are an important prerequisite for the internal life of bearings to be fully utilized.

Overall, rolling bearing grease will play an essential role in:

1. Reduce friction. Lubricating grease forms an oil film between the rolling element and the inner and outer rings, as well as between the cage and the outer ring of the rolling element. This liquid lubricating film can reduce and prevent metal contact, greatly reducing the wear between the friction parts of the bearing, and also reducing the heat generated by their mutual friction.

2. Anti scratch. Bearings will undergo elastic deformation between rolling working surfaces under load; When there is a phenomenon of biased load in the bearings, relative slip will occur between the rolling working surfaces. Liquid lubricating film can greatly reduce the scratches caused by the above phenomena, thereby extending the fatigue life of bearings.

3. Heat dissipation. Lubricating grease can dissipate the heat generated by the rolling working surface through rolling flow and conduction.

4. Absorb shock and reduce noise. Lubricating oil film can absorb some energy and partially convert concentrated loads into distributed loads, playing a role in shock absorption and noise reduction.

5. Sealing. Lubricating grease also plays a role in preventing dust, moisture, and other substances from entering the rolling working surface of bearings. The bearing grease applied in some oil seals is purely for filtering purposes.

6. Rust and corrosion prevention. Rolling bearing grease is generally a good rust and anti-corrosion agent, which can prevent bearing rust.