Just been reading problems with Bosch pump dismantling, in particular the removal of the triangular headed bolts.
I constructed a tool using a short length of 15mm electrical conduit, welded 3 blobs on the inside edge, and carefully profiled these to fit the bolt head using needle files. You just require to taper the end of the tube as clearance is tight.
Picture below.
The first method I used was to tack weld a normal nut onto the triangular head, then used a normal socket.
