[Richard]

Did the add-a-leafs come with any instructions? Looks like it should install directly under the main leaf. What I have done in the past is clamp existing spring pack and then remove the center pin, disassemble pack. Assemble spring pack with new leaf in proper location using a long bolt that will reach through all the leafs. Bolt should be fully threaded. You could also use a piece of all thread double nutted at one end to create a bolt. Draw the pack together using the bolt and a nut. Clamp pack, remove bolt and replace with new center pin. Will probably have to trim excess off of new center pin bolt.