Car running deviation is a common problem. In most cases, the problem can be solved by doing four rounds of positioning. But sometimes, how to do four rounds of positioning is not good. This must be caused by other reasons. We must find a solution to the problem so as to thoroughly cure the malfunction of deviation. In addition to the four wheel alignment misalignment, the main factors that can cause the deviation may be: 1. The defective brake return of a wheel is not complete. This is equivalent to a partial braking of the wheels on the side, and driving will inevitably run away. During inspection, the temperature of the hub can be felt, for example, a wheel exceeds a number of other wheels, indicating that the wheel's brake is not in good position. 2, the air pressure of both sides of the tires is different. Different tire pressure will make the tyre different in size, and it will run away when it rolls up. 3, the front shock absorber spring deformation on both sides of the buffer is inconsistent. The spring of the shock absorber can be judged by comparison after pressing or disassembling. 4, the tire patterns on both sides are different or patterns are not as high as deep. It is best to use the same type of tires all over the car. The minimum two tires at the minimum front axle and rear axle must be the same, and the pattern depth must be the same, and the wear limit must be replaced. 5, the vehicle chassis components wear too large there is abnormal gap. The steering rod ball head, the supporting arm rubber sleeve, the stabilizer bar rubber sleeve and so on are common parts with too easy clearance. The lifting vehicles should be carefully examined. 6. The front damper is invalid. When the front shock absorber fails, it will hang two high and low in the vehicle running, and the force will be uneven, leading to deviation. The absorbance of the shock absorber can be detected by the special vibration damping tester, and the quality of the shock absorber can be judged. 7. The overall deformation of the frame. The wheelbase difference between both sides is too large, exceeding the maximum allowable range. It can be measured by tape measure. If out of range, it must be calibrated with the calibration table.