After talking to the Claptrap and accepting a mission to repair them, they can then be restored with a Repair Kit. Once repaired, the Claptrap will then offer a reward of a Backpack SDU (Storage Deck Upgrade). Claptraps rescued on the second playthrough may not yield a Backpack SDU however. The first five in Borderlands have been known to have a chance of awarding them, while later Claptraps have not been seen to do so. It is very rare for the Claptrap in Lockdown Palace to reward a Backpack SDU on playthrough 1 and has not been seen to award one on playthrough 2.