The assembly process of third-generation automotive wheel hub bearings includes five stages: preliminary preparation, component disassembly, old bearing disassembly, new bearing installation, and component reset. Special tools are required and operating specifications must be strictly followed. The specific process is as follows:
1. Preliminary preparation
Tool and consumables preparation
Special tools: press machine, puller, clamp pliers, ball head pliers, wire hook, torque wrench (accuracy ± 5%). 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
Operate in a dust-free workshop (ISO 14644-1 Class 7 or above) to avoid dust entering the interior of the bearings.
. Maintain an ambient temperature of 15 ℃~30 ℃ to prevent installation errors caused by thermal expansion and contraction.2. Component Disassembly
Vehicle Fixing and Tire Disassembly
Drive the vehicle onto the lift and secure it with a safety bracket to ensure stability.
. Use a tire wrench to loosen the bolt and remove the tire. Disassembly of brake systemRemove 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.Disassembly of steering system
Remove the ball nut of the steering rod and use ball pliers to separate the steering knuckle from the steering rod (do not knock).
. 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.III. 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).
.Separation of bearing inner race
Use a puller to remove the bearing inner race.
.Remove the retaining spring
Use retaining pliers to remove the retaining springs on both sides of the bearing seat hole.
.Press out the old bearing
Use a press and circular pad to press out the old bearing from the steering knuckle, with a pressure controlled at 50-100kN and a speed ≤ 2mm/s.
.4. Installation of new bearings
Cleaning of seat holes
Wipe the bearing seat holes with a dust-free cloth dipped in alcohol to 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.
. Installation of retaining springFirst, install the outer retaining spring of the steering knuckle to ensure accurate positioning.
.Bearing pressing
Use the outer ring of the old bearing as a cushion block, slowly press the new bearing into the steering knuckle, control the pressure at 50-100kN, and 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 cushion block to press the wheel hub into the bearing, ensuring that the bearing inner ring is evenly stressed.
.Fifth, Component Reset and Inspection
Bolt Tightening
Reinstall the two bolts of 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.
Reinstall the brake disc with a torque of 25N · m.
Reinstall the brake caliper with a torque of 25N · m.
Reinstall the tire with a bolt torque of 110N · m. 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).
Function check
Rotate the wheel hub to check if it is smooth, without any 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.