I have had this problem with my wife's Montero as well. They all use cheap metal in those places. Most of the time it is a bolts.
For the last 4-5 yrs I have been putting this on the thread before putting them back in and it seams to do the trick.
For the last 3 yrs I have been using Amsoil oil, so had to remove them only once a year and no issues.