The biggest problem with vacuums is the car wash owners don’t maintain them properly. Vacuums are the highest income generator on the property and they need to be maintained, be it a 2 motor or 3 motor they need to be maintianed. We test and clean the vacuums out every day, we change the door gaskets every year and we change the motor brushes every year. I’ve gotten complaints that the vacuums suck to hard, LOL.