The phenomenon of the brake shoe nonaffine wear at Position 1 and 6 has been common since DF 4 series locomotives have been put into service.

• 东风4系列机车自投入运用以来,其1、6位闸瓦偏磨现象普遍存在,而且间或机车缓解时出现闸瓦贴靠轮箍踏面,造成轮箍松弛。