I've had 3 pumas, 300,000km+ between them the only thing that came close to stopping me was a vacuum pump on the 08 model and a rubbed thru radiator hose on the 12 model.. Having said that, I've never been totally immobilised with a breakdown. If your vacuum pump is one of the early ones and hasn't crapped itself, I would put the new one on and carry the old as the spare, that way you get to fit it in a non remote situation so that if you do need to do it in the sticks it won't be any thing new to you..maybe also do a fuel filter change to ensure if you pick up dirty fuel you can change the filter and get the thing going again..the pumas are really pretty bullet proof and simple despite the nay Sayers on some forums..sounds like a great trip, have fun!