Use closer maintenance, repair？

       Install the door closer in a week to 10 days or so, you should check all the screws, and re tighten again.

      Door closers should be regularly checked after putting into use, check the contents are: mounting screws are loose and lost, and the door or the door frame is connected with the arm collision, the door body is deformation and looseness, the buffering effect is closed, the gear shaft oil leakage.