It is much nicer to work on this if you first give it a thorough cleaning. To do this you either need to remove the ink-soaked pads, (some of which are glued in), or wash the entire assembly with the pads in place, which means you will need to leave them a long time to dry.

My replacement spring, shown in these pictures, was wound from some fine music wire I had on hand, It is too flimsy, but seems to work OK. You should use a more substantial spring than this.