Wirtgen w2000

Hey guys I’m at a loss right now. I’m working on this machine and they want me to change the bearings at the bottom of the conveyor belt. I can access 3 of the 4 bolts on the block but the forth is directly behind the mount for the front of the drum on the arm that goes up and down. How on earth do you access that to get the bolt out? 06200508 is the serial number