Keep the pump driver free of debris so the internal parts operate efficiently and have less wear.
Refer to the parts list and schematic and use the repair kit to disassemble the driver. The driver consists of a shaft, piston, cylinder, compression springs, retainer, plug with quick disconnect, and several o-rings and retainer rings.
Inspect the parts for wear as you remove them. Place the parts in order to aid in re-assembly. When you see the part that is cracked or worn, consult the parts list to order the replacement part. Once you have the new part or parts re-assemble the driver according to the schematic in the kit, making sure all seals are tight and the new parts are lubricated.