Cerwin Vega Fan

Window motor is starting to go out so I'm swaping it out for new one (again). Last time I changed the motor I noticed one of the rollers was cracked and did not want to stay in the tracks. So when I change the motor this time around I'm going to change one of the rollers too. How hard is it to change one of these rollers? Looks pretty stright foreward just wondering who has done this before.





Thanks