96' E320 Metal Key will not spring out
 

The metal part of my key will no longer spring out from its fob when you press the little button. It used to work like a switch blade .. now its limp and won't leave the fob ... you have to pry the metal key out with a finger nail or a pen point. I tried spraying silicone and working it into the key bearing ... but no use .. the spring has lost its oomph.

Is there a fix for a limp spring? Can one buy a key case and transfer the guts? thanks for the help.

:confused: PS: This is the "working" fob ... this one is synchronized ..but the other one won't synchronize ... I'd like to get at least one working key for my wife to use.