The general adjustment method of wheel bearing tightness is: after the wheel outer bearing is positioned, screw in the bearing adjusting nut while turning the wheel until the wheel is tightened by hand, then retreat the adjusting nut 1/6- 1/4 turns, and then tighten the lock nut. The above methods are often used to adjust the rear wheels of Yan 'an 250, Tedora 148 and Nissan TKL-20 cars, but the number of laps after tightening is different between Tedora and Nissan cars. Some cars, such as Isuzu TDJ and SJR cars, when adjusting the tightness of the rear wheel bearing, first screw in the bearing adjusting nut, and then slowly unscrew the nut until it is very laborious to turn the wheel bearing. Hang a spring scale on the wheel bolt of the wheel, and pull the wheel in the tangential direction with a force of 2030 N (install the brake drum), which is just suitable for pulling the wheel to rotate. If it is a new bearing, the pulling force should be 70-90 N. When adjusting the tightness of the steering wheel wheel bearing, it is necessary to tighten the adjusting nut first, and conduct the test with a pulling force of 200-300 N. When the wheel can just be pulled to rotate, stop screwing in the nut, turn the wheel left and right for 2-3 times, and then loosen the adjusting nut until the wheel can be pulled to rotate with a force of 10-25 N: Some. For example, in Mercedes-Benz 2026, it is stipulated to tighten the adjusting nut with a torque of 300 Nm, then loosen the nut 1/8 turns and install the thrust washer. After tightening the lock nut with a torque of 500-550 Nm, check the axial clearance of the wheel. This gap should be in the range of 0.03-0.05 mm If the gap does not meet the requirements, it should be adjusted again until the gap is suitable. For another example, when adjusting the tightness of the ift bearing on the front wheel of Nissan TKL-20 automobile, the adjusting nut should be tightened with a torque of 400 Nm. After the wheel rotates for 2-3 turns, the nut should be loosened by 1/6- 1/4 turns, and then the wheel is rotated for 2-3 turns. Then, measure the tension of the wheel V when it starts to rotate with a spring scale and adjust it. Some models not only require the adjusting nut and locking nut to be tightened with a certain torque, but also require the adjusting nut to be tightened and loosened twice, and the tightening torque and the number of turns to be loosened are also different. For example, Hongyan 26 1 car, when adjusting the steering wheel tightness, first tighten the adjusting nut with a torque of 500 Nm, then loosen the nut 1/4 turns, then tighten the adjusting nut with a torque of 100 Nm, then loosen 1/8 turns, and then install the locking ring with a torque of 25 Nm. When adjusting the tightness of the wheel bearing of the middle and rear wheels, first tighten the adjusting nut with a torque of 600 Nm, then loosen it with 1/6 turns, and then tighten the lock nut with a torque of 800 Nm.