The device comprises at least one pressing member and an attachment member for attaching it to a wind turbine part, for example, a blade root, which may have a relative movement with regard to a first part, for example, a bearing in a pitch blade mechanism, the first part having a seat into which the joint is to be fitted. Upon relative rotation between the first parts, the pressing member presses the seal into the seat. A method for fitting the seal into the seat is also provided. Operations of maintenance or partial or complete replacement of the seal can be carried out in situ on the wind turbine and also on pitch bearing manufacturing easily and effectively.