To service Hilti and Duss are 2 names of expensive professional brands with the highest quality metals and are most delicate brands in the world to service .with high marketing technical developments
The technic in these brands are like no other brand , if it has its working hours done , be aware to do this on your own without this
knowing that there may be a range of collaborating very special bearings present a coplete collaboration that must be replaced there are special poor-tolerance bearings it likes they where damaged if you feel this parts but its neccesary and very special calculated and the (Hilti )Turmopol oil is also very very expensive and sometimes there are ceramic rings used for the batte piece but in any case costs all a lot of money and its wasted in a very short time if not knowing how to service , if you want to take this yourself, these brands are not toys for Fixya and can harm more than it could happen if you are not aware of the cooperation of the various components in this machines and sometimes hidden tricks to it may be, for example, to release an armature that in a special seal is present which is not just available separately outside of the anchor.
So be warned, it does all depend on the model and year out, service on your own without the right tools can make more damage than you may expect