water hammer fixed?

i spoke 2 you afew days ago about the noise from my pipe work due 2 my hot water taps. you advised me to go into the loft and hold up the ball cock when the noise started and it stopped when i did so. i have now replaced the full stem (valve) of the ball cock in the header tank and this has fixed the problem.just 2 let you know this has worked and only cost me £4.98 from B+Q....THANKS.....FOR YOUR HELP.....