The Water-works is a site of importance to the dwarves who wish to remain in Moria. Once such dwarf, Foreman Indrith, has made it a mission to repair the channel there.
'If we sheared a gear, and I believe that we did, we need to get a new one. During my time in the Great Wheel, I have explored many of the tunnels that feed these wheels.
'On one of my journeys, I spotted a gear in a room beside the tunnels. However, I thought nothing of it, and left it where it lay. I believe you will need to recover this gear before our work can continue.
'You can make your way deeper into the Great Wheel from The Drowned Deeps or through the gate across the way. Hurry!'
Foreman Indrith believes that you sheared a gear while trying to force the wheel housing in the Great Wheel to start turning once more. He believes another gear is located in the tunnels of the Great Wheel.
Foreman Indrith is in the Wheel-house, beneath the Great Wheel, south-west of Hulwul-nefekh.