The first generation of automotive wheel hub bearings, as the mainstream technology solution from the 1960s to the early 1980s, covered three core aspects of installation, adjustment of pre tension, and maintenance, as follows:
1. Installation method
Tool preparation
Basic tools: lift, wrench, screwdriver, socket, puller, press, clamp, etc.
Alternative solution: If there are no specialized tools, newly removed waste bearings can be used as cushion blocks to assist in installation.
.Vehicle fixing and component disassembly
Drive the vehicle onto the lift and securely fix it, remove the front wheels to expose the work area.
. Remove the self-locking nut at the end of the half shaft (another person needs to step on the brake pedal to provide reverse torque).Separate the braking and steering system:
Remove the brake caliper and hang it on the vehicle body.
. Remove the ball nut of the steering rod and use ball pliers to separate the steering knuckle from the steering rod. Remove the connecting bolts between the steering knuckle and the shock absorber, as well as between the steering knuckle and the lower swing arm.Dismantling of old bearings
Use a special tool or sleeve to push the wheel hub out of the steering knuckle, and the inner ring of the bearing will fall off with the wheel hub.
.Use a puller to remove the inner ring of the bearing on the wheel hub.
Use clamp pliers to remove the positioning clamps on both sides of the steering knuckle bearing seat hole.
. Use a press and circular pads to press the old bearing vertically out of the steering knuckle, avoiding tilting.New bearing installation
Cleaning and lubrication: Clean the bearing seat holes on the steering knuckle to ensure that there are no impurities, dirt, or old lubricating grease;
; Apply specialized lubricating grease thoroughly to the seat hole.Press in the new bearing:
Install the outer retaining spring of the steering knuckle to position the new bearing.
.Use the old bearing outer ring as a cushion block and press the new bearing vertically with a press to ensure that the outer ring is evenly stressed.
. After the bearing is fully pressed in, install the other side retaining spring.Use the old bearing inner ring as a cushion block, press the wheel hub into the bearing, and ensure that the inner ring is evenly stressed.
.Check installation status: Rotate the wheel hub to confirm that it rotates smoothly without any abnormal noise, and also check if the oil seal is intact.
.Component reset and fastening
Install the steering knuckle, brake caliper, steering rod, and other components in reverse order of disassembly.
.Strictly tighten the bolts according to the torque specified in the vehicle maintenance manual:
Connecting bolt between the steering knuckle and the lower swing arm: 35 N · m
Connecting bolt between the steering knuckle and the shock absorber: 95 N · m
Bottom nut of the steering rod: 35 N · m
Install the self-locking nut at the end of the half shaft and tighten it to the specified torque (such as 265 N · m). If necessary, ask others to assist in providing reverse torque.
.Secondly, adjust the preload
Purpose of preload adjustment
Ensure that the bearing is neither too tight (causing increased friction, heating, or even damage) nor too loose (causing vibration, noise, or early failure) when subjected to load.
.Adjustment steps
Place the outer bearing of the wheel hub in the correct position and gradually tighten the adjustment nut of the bearing while rotating the wheel hub.
. After the wheel hub reaches a stable state, rotate the adjusting nut in the opposite direction by one sixth to one fourth of a turn. Perform a pull test with a force of 200-300 Newtons. Once the wheel hub can rotate slightly, stop tightening the nut. Rotate the wheel hub 2-3 times left and right, gradually loosen the adjustment nut until only 10-25 Newtons of force is needed to make the wheel hub rotate.III. Maintenance
Regular inspection
Check the wear, looseness, and abnormal noise of the bearings.
. Check the cleanliness and integrity of the bearing seat holes and oil seals.Lubrication and Sealing
Early wheel hub bearings required regular lubrication (such as adding lithium grease every 50000 kilometers), but modern maintenance free bearings have enclosed lubricating grease and do not require additional addition.
. If lubrication is required, an appropriate amount of specialized grease should be used, and cleanliness and quality should be ensured.Replacement and Repair
Once serious wear, looseness, or abnormal noise problems are found in the bearings, they should be replaced or repaired in a timely manner.
. Due to similar working conditions, even if only one of the front wheel hub bearings is damaged, it is recommended to replace them in pairs to ensure balance.