It’s to deter people from using it for general grinding... you have to unbolt it and remove the cover.
I have no clue how old the grinder is... I’ve only worked here for 8 years. It’s been like this as long as I’ve been here.
Steering axles allow the trailer to kick out. If the trailer doesn’t have enough weight, they have hydraulic cylinders that attach to the back of the truck to force the trailer to stay out. Those cylinders can be put in bypass to allow to trailer to act like a normal trailer.