Iirc Mercedes had it catch fire on their test track and didn't want to convert because of it. If you look on the labels for the new ones they have the flammable symbol.
Onto the original question, what is the reason to switch? If it's cause the a/c isn't cold you will need to verify it's not leaking anywhere before you start my else. Also if the lines have been off longer then a couple hours replace the dryer.