My pretreatment machine is dripping pretreat out of the nozzle

Answer - This is due to the nozzle and/or check valve. The check valve is most likely the issue if it drips quite a bit. The nozzle would drip only one or two drops if it was bad. If it's the check valve it would stream out quite a bit of fluid. This is what stops the fluid flow after the spray is finished. It’s usually from not cleaning it very well (or well enough), so the check valve is getting stuck open allowing the fluid to drip out after the spray. Image number 4 in the diagram below is the check valve. The nozzle cap twists onto the nozzle body to hold the check valve in place.