Are you just replacing the skirt or looking at rebuilding the entire bumper? Rebuilding and in the same process of replacing the skirt (a $1.00 part) with a new bumper body only takes 30 minutes and makes your game come to life. While you are there replace the coil sleeve (another very cheap part).
So it you are looking at replacing the skirt, do a rebuild while you have the bumper apart 
On how to replace see: http://www.pinrepair.com/em/index2.htm#pops
Thanks to all for your responses. I have heard so many times that these are a pian to do and so wanted to clarify whether it was a myth or not. Sounds likes its BUSTED and I won't hesitate rebuilding one when the time comes. Will also check out the above link. thanks
