The assembly process of third-generation automotive wheel hub bearings is as follows:
Preliminary preparation:
Tool preparation: Prepare special tools such as press machine, puller, clamp pliers, ball joint pliers, wire hook, torque wrench (accurate to ± 5% torque), as well as consumables such as lithium based grease (NLGI level 2), dust-free cloth, silicone sealant (temperature resistance -40 ℃~150 ℃), etc.
Protective equipment: Wear anti-static gloves, goggles, anti smashing shoes and other protective equipment to ensure safe operation.
.Environmental requirements: Operate in a dust-free workshop (ISO 14644-1 Class 7 or above) to avoid dust entering the interior of the bearing;
; Maintain an ambient temperature of 15 ℃~30 ℃ to prevent installation errors caused by thermal expansion and contraction.Disassemble old bearings:
Vehicle fixation: Drive the vehicle onto the lift and secure it with a safety bracket to ensure stability.
. Tire disassembly: Use a tire wrench to loosen the bolts and remove the tire. Disassembly of brake components: Remove the brake caliper and hang it on the vehicle body with a steel 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 components: Remove the ball nut of the steering rod, and use ball pliers to separate the steering knuckle from the steering rod (strictly prohibit knocking); 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.
Bearing disassembly: Use a special tool to push the wheel hub out of the steering knuckle (if no special tool is available, a matching sleeve can be used as a substitute); Use a puller to remove the inner ring of the bearing; Use clamp pliers to remove the clamp springs on both sides of the bearing seat hole; Press out the old bearing from the steering knuckle using a press and circular pads.
Installing a new bearing:
Seat hole cleaning: Use a dust-free cloth dipped in alcohol to wipe the bearing seat hole 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 spring: First, 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 (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 reset and fastening:
Steering joint reset: Reinstall the two bolts of the steering joint 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.Brake component reset: Reinstall the brake disc, torque 25N · m;
; Reinstall the brake caliper with a torque of 25N · m. Tire installation: Reinstall the tire with a bolt torque of 110N · m. Half shaft nut tightening: 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).After installation inspection:
Rotation inspection: Rotate the wheel hub to check if it is smooth, without any jamming or abnormal noise.
.Vibration detection: Use a vibration analyzer to detect the vibration frequency of the bearing (≤ 2.8mm/s), ensuring that there are no abnormalities.
. Sealing inspection: Check if the oil seal is intact and there is no leakage.