X61 Tablet - Fixing a broken shift key

[hkspvt]

My left shift key recently came off as I was cleaning my keyboard. I got it back on without much drama, but now the spring feels weaker and getting the key to actually respond requires a lot more force. I pulled the key off and re-attached it again to no avail.

Needless to say, this is driving me nuts and damaging my pinky. Has anyone else run into this? Short of a full keyboard replacement, how did you fix it?

-HKS