Hi Soorian,
To be honest i have not done mine, ha,ha,ha.....
mine only happens when i wash the car and water is directly sparayed need the door area....other than that when it rains ...not that bad yet.....
i actually read it on another thread on this forum, i think u just need to get the mechanic to put some sort of sealent for it..........
not sure where u live, but if around PJ u might wanna give M Laju a try.......