Thanks for your comments... Its great to know that its easy and I can do it myself. If I'm asking any plumber here.. they say - mafi mushkil (its the first term) then say - hoga ek sau bees...!!

Recently I stopped the leakage of my shower tap with a 50dhs washer. Where the plumbig guys told - ek sau beez aur naya shower chahiye...!! It's Qatar.>!