we just added 1 full lenght leaf under the main leaf , had them made at a local spring shop , not sure on the Arc
jack up the car , use stands under the frame ,undo or cut off the U bolts , raise the diff off the spring , remove the fold over spring clamps , undo or cut the center bolt , install a new center bolt slide the new leaf up to the main leaf , install all the original leafs onto use a C clamp to hold the leafs togther , do up the center bolt , reinstall the shock plate & U bolts , re-install the fold over clamps at least on the front of the spring , tighten everything & recheck after a few miles
