The installation of third-generation automotive wheel hub bearings must strictly follow the operating specifications, combined with its highly integrated characteristics (double flange design, integrated ABS sensor). The following are specific installation steps and precautions:
1. Preparation before installation
Tools and materials
Special tools: press machine, puller, clamp pliers, ball joint pliers, wire hook, torque wrench (accurate to ± 5% torque). Consumables: Lithium based grease (NLGI grade 2), dust-free cloth, silicone sealant (temperature resistance -40 ℃~150 ℃).
Protective equipment: anti-static gloves, goggles, anti smashing shoes.
.Environmental Requirements
Cleanliness: Operate in a dust-free workshop (ISO 14644-1 Class 7 or above) to avoid dust entering the interior of the bearing.
.Temperature control: Maintain an ambient temperature of 15 ℃~30 ℃ to prevent installation errors caused by thermal expansion and contraction.
.Component inspection
Bearing status: Check that the magnetic coding ring (ABS sensor) has no cracks, and that the brown side of the oil seal faces inward.
.Matching surface: The diameter tolerance of the shaft neck is H7 level (± 0.015mm), and the perpendicularity of the bearing seat hole is ≤ 0.02mm.
2. Disassemble the old bearing (if it needs to be replaced)
Vehicle fixing
Drive the vehicle onto the lift and fix it with a safety bracket to ensure stability.
.Component removal
Tire removal: Use a tire wrench to loosen the bolts and remove the tire.
.Braking system:
Remove the brake caliper and hang it on the vehicle body with a wire hook to avoid stress on the brake pipeline.
. Loosen the fixing bolts of the brake disc and remove the brake disc.Steering joint separation:
Remove the ball nut of the steering rod and use ball pliers to separate the steering joint from the steering rod (do not strike).
. Remove the 2 bolts from the steering knuckle and shock absorber, and the 3 bolts from the lower swing arm, and then remove the steering knuckle.Removal of old bearings
Wheel hub ejection: Use a special tool to eject the wheel hub from the steering knuckle (if no special tool is available, a matching sleeve can be used as a substitute).
.Bearing separation:
Use a puller to remove the inner ring of the bearing.
.Use snap pliers to remove the snap springs on both sides of the bearing seat hole. Use a press and circular pads to press the old bearing out of the steering knuckle.
3. Install new bearings
Cleaning and lubrication
Seat hole cleaning: Use a dust-free cloth dipped in alcohol to wipe the bearing seat hole, remove oil stains and rust.
.Lubricating grease application: Apply lithium based lubricating grease (thickness 0.01~0.02mm) evenly on the inner and outer raceway and rolling element surfaces of the new bearing.
.Bearing press in
Installation of retaining spring: First, install the outer retaining spring of the steering knuckle to ensure accurate positioning.
.Bearing press in:
Use the outer ring of the old bearing as a pad and slowly press the new bearing into the steering knuckle (press pressure controlled at 50-100kN, speed ≤ 2mm/s).
. After the bearing is fully pressed in, install the other side retaining spring.Wheel hub pressing: Use the old bearing inner ring as a pad to press the wheel hub into the bearing, ensuring that the bearing inner ring is evenly stressed.
. Component resetSteering knuckle installation:
Reinstall the two bolts connecting the steering knuckle and shock absorber, with a torque of 95N · m.
Reinstall the three bolts connecting the steering knuckle and lower arm, with a torque of 35N · m.
Braking system:
Reinstall the brake disc and apply a torque of 25N · m.
Reinstall the brake caliper with a torque of 25N · m. Tire installation: Reinstall the tire with a bolt torque of 110N · m.
IV. Key precautions
Prohibited operation
It is strictly prohibited to strike the bearing (which may cause damage to the magnetic coding ring or deformation of the cage).
.It is strictly prohibited to disassemble or adjust the sealing ring (damaging the sealing may cause water and dust to enter).
Magnetic coding ring protection
When installed, the magnetic side should face the inside of the wheel and be stored away from magnetic fields (such as motors and speakers).
.Torque Control
The self-locking nut at the end of the half shaft has a torque of 265N · m (requires two people to cooperate, with one person stepping on the brake pedal to provide reverse torque).
Safety verification
After installation, rotate the wheel hub to check for smoothness, no jamming or abnormal noise.
. Use a vibration analyzer to detect the vibration frequency of the bearing (≤ 2.8mm/s) and ensure that there are no abnormalities.