I drive (but not own) a truck for a living so I'll put out what I can.
Well, a current DOT/State inspection is a big plus. This won't help you with the firefighting bits but it should provide some assurance that the truck doesn't have any glaring safety defects. If it hasn't had one, getting one done along with a PM is a good thing to spend a little money on. For an ordinary truck a PM and an inspection could be done for $200 or so. An oil analysis might be a good thing to do as well before sinking a lot of money into the truck. Probably getting recommendations, finding a shop, and getting an approximate idea of what they charge would be a good thing to do before buying the truck.
If you are not able to get a mechanic to check the rig before you buy, my suggestion would be to grab your state's CDL manual from the local DMV and look over the sections on pre trip inspection and air brakes then run through the pre trip inspection checklist when evaluating a vehicle.
Well, a current DOT/State inspection is a big plus. This won't help you with the firefighting bits but it should provide some assurance that the truck doesn't have any glaring safety defects. If it hasn't had one, getting one done along with a PM is a good thing to spend a little money on. For an ordinary truck a PM and an inspection could be done for $200 or so. An oil analysis might be a good thing to do as well before sinking a lot of money into the truck. Probably getting recommendations, finding a shop, and getting an approximate idea of what they charge would be a good thing to do before buying the truck.
If you are not able to get a mechanic to check the rig before you buy, my suggestion would be to grab your state's CDL manual from the local DMV and look over the sections on pre trip inspection and air brakes then run through the pre trip inspection checklist when evaluating a vehicle.