They removed hose clamps and then started disconnecting umbilicals from the broken space station coolant pump. However, difficulty unplugging one of the ammonia lines consumed a couple of hours and a leak seen from that connector once it finally cooperated prevented the astronauts from progressing any further in their work.

Removing the old pump and stowing it on a payload attachment bracket on the Mobile Base System on the station's truss while preparing the replacement pump for its removal from a stowage platform adjacent to the Quest airlock and its installation on the truss during a third spacewalk.

Installation of a spare ammonia pump module on the S1 Truss.