Air brakes have absolutely no determination on whether or not a vehicle requires a CDL. Zip. Zilch. Nada. Not just in Maryland, but in any state.
That depends on which country you live in.
Yes
Air brakes have absolutely NO effect on whether a vehicle requires a CDL or not.
No - you do not need to have the truck running.
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.
you do need a licence to drive a boat in Maryland
The braking system doesn't determine whether or not a vehicle requires a CDL.
Whether a vehicle has air, hydraulic, or air-over-hydraulic brakes has zero determination on the class of license required to operate it.
To drive a semi truck, you need a specific driving license that allows you to drive that class of vehicle. As well, as proper education and training such as driver's ed.
Brakes will be dependent upon what type of truck you have and what you are doing with your truck. There is a website that can help brakeworld.com will help walk you through the right selection of high performance brakes for your truck.
Yes. You can drive that vehicle with either a Class B or Class A CDL.
You need to have the abs checked for codes. Then you can diagnose cause.