My 25 year old Bosch PFZ 550E reciprocating saw suffered a sudden death while pruning heavy roots. I took it apart and identified the broken part, a guide bracket which I've ordered for $6.00. There is some old grease in the mechanical area and I'd like to replace or add grease when I reassemble it. The electrical side doesn't appear to be well separated from the mechanical side and I don't want the grease to migrate into the electrical side. And I use the saw for pruning so it's used in all sorts of positions. I have some 20 year old wheel bearing grease that looks about the same consistency. Would that work? I also have some Lubriplate and Molybdenum grease gun grease but they both seem pretty thin. Other suggestions? The old grease still looks reasonably clean. Should I leave the better grease and just add a bit, or replace it all?