very easy to change , removing the battery gives alot more room , there is an idler wheel in the middle of the two pullies , one bolt holds the idler in place and holds adjustment as the idler bracket is slotted , newer idlers have a pointer that shows when the adjustment is correct , 3:00 position is the correct adjustment , it will be facing right at you on a horizonal plain , the pointer breaks alot and may not move when you adjust it , you adjust it with a pry bar between the top of the pump mount/bell housing and the idler bracket , it is hard to get two hands in there hold the idler to adjustment with the bar and then tighten the bolt , so if you snug the bolt enough so that the idler will still move but hold it's spot when you let go , you can pull it where you want then get in there with a ratchet and tighten the bolt , if the pointer is not working you can still use the idler if the bearings are good , you have to adjust the belt by feel unless you have a Bobcat drive belt adjustment tool , which set it at 15 lbs of pull in a one inch pull -----------as far as if you need a new belt , you will have to look at it , sometimes the belt will spit into 2 or 3 seperate belts if the belt has cracks on the inside between the ribs then I would change it ,