My vacuum line that controls the a/c airflow diverter has fallen off for the 4th time. The air is only blowing through the floor and defrost vents. It's falling off where the vacuum line boot (female) attaches to the vacuum unit (male) inside the top of the dash behind the radio. I've put it back on several times, and tried putting a zip-tie around the boot to squeeze it tight around the joint, but it's off again. I'm thinking this time that I might put some silicone sealant around the male side and see if that will glue it together. Any ideas how I can make this stick??? Thanks.