You need a service kit around 15 pounds and whilst you have mira apart you might as well renew the pistons a set of these are around 12 pounds. You can usually get the temp control knob off with two screwdrivers prising from both sides. Then take off the spring washer and remove the flow control knob ,undo the big nut and you will expose the innerds just follow the diagram supplied with the service pack and then refit in reverse order making sure everything is in the right place be careful with the small key used for adjusting the temp the square bit at the top fits into a recess in the main body of the mira if not put in the right place the mira will dribble when put back together. having done all this you should find a drip free mira. best of luck
Nick
October 2007