My suggestion - Since you bought them from Inland RV, I would ask them on the proper removal of the old ones, cleaning of the area around it and the installation procedure of the new ones and then post your discoveries.
Maybe you could take a couple of pictures on how you do it. Before, during and after the installation, for us all to see.
-"You want to make it two inches - or, if you're working in centimeters, make sure it's enough centimeters for two inches."-Red Green