Where can I find a replacement hammer pipe part 1617000448

Working on a number of hammer drills at my job including Bosch drills, the most common reasons for it to drill and not hammer is either to do with the hammers or the connecting rod and piston in the gear case.

So inside that tube that you listed the part number for are floating hammers that have o-rings and seals on them. Over time they tend to flatten and not seal fully in the tube and that prevents them from moving. It can be that they are old and worn, that they cracked and frayed, that the tube itself has debris or is not greased fully anymore, or the tube may have gouging internally from debris preventing a complete seal. With the exception of the gouging you shouldn't need to replace the tube with the part number you included and can usually get by with a seal kit which is part number 1617000446. Through my job I get parts from Bosch directly but personally I tend to go through E-replacement parts which I linked to.

Now it is important to take the gear case housing off and inspect the connecting rod because those tend to break more often than not, and if broken it won't move the piston to engage the hammers in the tube, so you are looking at part number 1617000843.

Either way you will be disassembling the unit and regreasing it along with seal replacements, to be safe during these repairs and to prevent having to do it a second time I usually just put a seal kit every time it comes in to service.

Here is a breakdown and with interactive part numbers 11247 Breakdown