Fault phenomenon
     A Nissan pickup car, in the 40-6Okm / h speed section, the chassis "Weng Weng" abnormal sound, and was gradually increasing trend. When the speed increased to 70km / h or more, abnormal sound disappeared.
     Troubleshooting and troubleshooting
     Maintenance personnel after the road test, still can not diagnose the abnormal parts, then support the drive axle in situ test. When the speed of 40-60km / h, no abnormal sound appears, indicating that the car drive system without exception, abnormal sound from the front axle. After repeated trial auscultation, found the sound like the front wheel. Further examination found that the front wheel of the crown part of the pit-like wear. Replaced the two front wheel after the test, abnormal disappear.
     Failure analysis
     After the front wheel of abnormal wear and tear, when the speed reaches a certain level, the tire due to uneven growth and abnormal sound. Maintenance personnel accordingly, but also lead to abnormal front wheel wear front wheel positioning, wheel bearing preload, steering knuckle (ball pin) and other related parts were overhauled. Is now driving 20000km, the front wheel wear normal, abnormal sound did not appear again.