Done this quite a few times but it depends on which lower seal plate you have , some have more clearance at the very bottom and just enough room to remove and install the timing belt without removing the lower pulley, did this last year on out airport tug (Harlan) got a few at this airport , had to tilt that top of the belt towards you from the top sprocket and middle sprocket , hope you have a warm place to do it because the belt is stiff when cold, if your luck and get it off that way put the new belt in hot water for a few , then quickly install the belt, make sure it is free of any oil after, oil attacks the rubber and the teeth will sheer off or the belt will stretch and brake later, (like a valve cover leak ) if you do have to pull the lower pulley you need a strap wrench to hold the pulley , first you need to have to put a spacer or something close on top of the bolt and hit it a few times with a large hammer , helps , use a long pull bar to remove the bolt , better if you have air you could use a air impact gun, hope this helps , to bad your so far away I would do it for you , later , Blaine in Mississippi