If it's a registered farm vehicle, then typically, no, although the licence requirements for vehicles exempt from CDL regulations vary between states - some states may require an upgraded non-CDL licence, and may require the air brakes test to be taken. If it's a commercial use vehicle, and not registered as a farm vehicle, then they would need a Class A CDL without an air brake restriction (there is no actual air brake endorsement).
No, the brakes have nothing to do with the drive shaft.
That depends on which country you live in.
Yes
Air brakes have absolutely NO effect on whether a vehicle requires a CDL or not.
You need to replace the rear brake pads and anything else the brakes may need. Driving without rear brakes would be foolish and dangerous. Good brakes are a number one priority.
It depends on a lot of things, such as where you drive them (hilly areas need more fuel than flat ones), how you drive them, what you're carrying...most drivers average between 6 and 7 mpg in their trucks.
The amount of weight they'll carry on those axles dictates whether or not they need single or tandem axles.
all you need is a socket set and a c.clamp drive safe
Air brakes have absolutely ZERO determination in whether or not a vehicle requires a CDL.
If you're driving a regular pick-up truck, you need your regular driver's license. If you want to drive bigger trucks, like semis, then you need a CDL, which stands for Commercial Driver's License.
15k seems rather soon for brakes to wear out, but if you drive a lot of city traffic, stop and go, or pull trailers frequently then its possible. Also if you drive like an idiot and slam on your brakes a lot then yes this is normal.
I need a diagram of ford F350 drum brakes on 1996 model 460 engine 4 wheel drive