Which assembly are you looking at that is four leaves?
It's not too complicated to install a new leaf though. It helps if you can jack up the rear end so the wheels are off the ground. You'll need a C clamp to hold the pack together as you loosen the centering pin. Once the pin is out, release the clamp slowly and slide the new leaf into place (in between the overload and the rest of the pack). Cut a little off the new centering pin the AAL gives you (just an inch or so - makes it easier to get it in), line up the holes and tighten the pin down. You can use the C clamp again at this point if its too hard to tighten by hand.
It's not too complicated to install a new leaf though. It helps if you can jack up the rear end so the wheels are off the ground. You'll need a C clamp to hold the pack together as you loosen the centering pin. Once the pin is out, release the clamp slowly and slide the new leaf into place (in between the overload and the rest of the pack). Cut a little off the new centering pin the AAL gives you (just an inch or so - makes it easier to get it in), line up the holes and tighten the pin down. You can use the C clamp again at this point if its too hard to tighten by hand.
