Abstract:The failure of abnormal temperature variation of the guide bearing was found for a hydraulic power unit in operation,the gap of the guide pad was also gradually increased,which resulted the increase of bearing swing.By the field test,it was found that the lower guide bearing tile gap was increased from 015 mm to 030 mm,the lubrication oil was deteriorated,and the wear and tear at different degree was found in upper and lower guiding bearing tile.Field test and analysis showed that the main reasons for the failure were the surface of the guide pad is uneven and the contact surface of the sliding rotor is too small.By the reparation of guide bearing tile and unit axis and the adjustment of guide bearing gap,the swing and vibration of the unit are improved obviously,and the guide bearing tile temperature shows stable basically.