After the China Dongfanghong-802 tractor works for a period of time, the front of the crawler will show different degrees of extension, which will lead to accelerated wear of the inner surface of the guide wheel rim, the crawler is easy to derail, and the working resistance increases during walking. Mainly caused by the abnormal operation of the guide wheel. If the axial clearance of the guide wheel is large, the wear gap between the guide wheel shaft and the shaft sleeve is increased, or the shaft is bent, etc., the guide wheel axis is not perpendicular to the longitudinal centerline of the locomotive, which will cause the crawler belt to stretch out.

　　Inspection Method

　　To judge whether the crawler is stretched out, the following methods can usually be adopted.

　　1: Visual inspection

　　Standing in front of the locomotive and visually inspecting, if the track is obviously inverted "eight", it can be determined that the track has been stretched out.

　　2: Measurement method

　　Measure the outer width of the two crawlers before and below the guide wheels. The normal value should be 1850mm. If the width of the outer sides of the two crawlers is much larger than the normal value, it means that the crawler has been stretched out. Repair method: If the axial clearance of the guide wheel exceeds 0.8mm, the clearance should be adjusted in time. If the bearing is excessively worn, it should be replaced. If the gap between the turning shaft and the shaft sleeve exceeds 5mm, the large and small shaft journals of the turning shaft should be welded, or the large and small shaft sleeves should be replaced to make the gap between the two meet the standard. If the bending amount of the turning shaft is less than 0.5mm within the allowable range, the insert earrings can be removed, and the left and right turning shafts can be reversed and assembled for use. If the bending amount of the turning shaft is too large, the turning shaft must be corrected or replaced with a new one.