580D Brakes

Hello to All. I have a 580D with extendahoe that I bought from a relative last summer. He owned the tractor for a few years, but did not have the resources to keep it properly maintained. He only fixed what was absolutely necessary to keep the machine running and digging. Naturally, there are many things I intend to repair when I get the time. Most importantly, the tractor has developed some brake problems. When the machine sits for a while, it feels like the brakes lock up, and it takes a lot of throttle to break it loose. Also, most of the time when the brake pedal is depressed, the brakes grab. I have dug quite a bit with it, and it digs good. If some of you can describe to me in detail how the brake system works on a 580D, I would appreciate it very much. I have located where to get a manual, but unfortunately, I am not good at reading technical documents. I have not bought the manual yet. Depending on what I hear from you guys, I may just opt to sell the machine and rent one when I need to dig. If it sounds like the brake fix is something I would like to get done, I will hire a mobile mechanic to do the work. I am too old to do it myself. Thanks. jfe