Try this,
Take the shear pin (bolt) out of the PTO shaft at the spreader gearbox. Remove and collapse the PTO shaft and install on tractor. Extend shaft and slip back onto gear box shaft. Reach inside spreader and turn agitator or turn distributor disk to align shear pin hole, install pin and tighten, you're done in less than a minute.
Take the shear pin (bolt) out of the PTO shaft at the spreader gearbox. Remove and collapse the PTO shaft and install on tractor. Extend shaft and slip back onto gear box shaft. Reach inside spreader and turn agitator or turn distributor disk to align shear pin hole, install pin and tighten, you're done in less than a minute.