Its possible to remove the lower bolt without removing the pulley that blocks it - but only just. You'll find that the bolt will juuusssttt clear the shocker enough for you to get it out, although it requires a bit of manipulation.

Try pulling the bolt out on a slight angle and working the shocker free.

I had the same problem as the original poster, went through 2 replacement shockers. The eventual solution was to replace belt, tensioner, pulley, basically the entire assembly. Been fine ever since. You could tell when things were getting worn, as the shocker would be red hot to touch.