How old is this grader?

Hello, I'm hoping someone can tell me about how old this "D" grader is. It's serial number is D-5597.  Thanks in advance from a newbie!

Thanks ! I guess it's a little newer than I thought.  It's missing the brake linkage on the bottom... is there any junkyard that parts these things out? A source for new brake parts?  

I hope I'm not getting in over my head. I've never used a grader or tractor of any kind and although mechanically inclined I've got no experience with diesel engines. A year ago we moved into a home a mile down a dirt road then realized it's not maintained. No one else seems to care but I cant take the washboard anymore. Gonna learn to use the grader... still looking for online tutorial videos of some sort.

I can give you a couple tips as an operator.  Make small adjustments and go as slow as possible if you are trying to make vast changes, and then go not quite as slow...lol.  Try to do you work after a nice rain, or water it down before grading.  If you have severe washboards or deep potholes you will need to either make a cut or scarify to deepest washboard or pothole.  cutting works if the ground is loose enough, otherwise you will need to scarify to get it loose enough to grade.  Once you get it ready to grade you can then take a pass on each side carrying your extra material to the middle to give you a nice crown, then once you get the hang of it you can take and roll everything from one side to the other, and then the next time go the other way.  Just keep in mind that small adjustments work better than large ones and each adjustment will change once the rear tires get to it, but with graders like the D their length aids in keeping smooth surface.