I'm bad about long messages, will try to keep this short. I installed the entire "Wet" suspension kit with the center pivot having the rubber bumper on my tandem axle Allison / Boat Mate trailer. Bought from etrailer, great people to deal with! I also changed the leaf springs. The original leafs were getting flat and the axles were bottoming out on the trailer frame. Original leafs are 1750 lb ratings, changed to 2400 lb rating springs. I disassembled the new leaf springs. At the end of each leaf is a sharp ridge like surface. This ridge is a result of cutting the spring with a high speed abrasive cutting device. This little ridge at the end of the leaf springs may be positioned in such a way to be in contact with the mating leaf. If so that little ridge will cut into the mating spring causing a bind along with a terrible ride. Grind those ridges off and radius the end of each leaf. I spread Royal Purple wheel bearing grease generously on all the surfaces between the springs. I cover the springs after assembly with covers that are removable. Result of all this effort is an ultra smooth riding trailer with no squeaks.