Mobile telescopic hydraulic crane, which is furnished with at least one service opening (48, 48') in the area of a telescopic secondary section (4), namely on its free terminal portion (42) and in particular at a suitable distance apart from the terminal portion (442) of the external tubular section (44) in the area of arrangement of at least one hydraulic connector (431) for connecting a flexible hydraulic pipe (43), which is on the other hand connectable with a hydraulic connector (432) on the free terminal portion (452) of an internal tubular bearing section (45), wherein said at least one service opening (48, 48') is available in a suitable shape and dimensions, which allow access there-through from the outside of each telescopic section (4) by means of suitable hand tool, which is required in order to establish or disassemble each hydraulically sealed connection between each flexible hydraulic pipe (43) and each belonging hydraulic connector (431) within said telescopic arm (4). Such measure then allows a quick and simple replacement of each hydraulic pipe (43) within the telescopic secondary arm (4), without significantly reducing the carrying capacity and reach of the crane.