MTG:
I’ve had the same problem with my ‘beaters. It happens after a while. See this link from ‘pedaldamnit’ to see how easy it is to take your ‘beaters completely apart:
http://pedaldamnit.blogspot.com/2008/04/crank-brothers-eggbeater-servicing-ii.html
As far as I know replacement springs are not available, but… Once in bits it’s relatively easy to re-tension the spring itself by bending the right-angled ends of the spring arms slightly – I’ve used a pair of mole grips to grab hold of them and bend. This bending will completely take up any slack that has developed in the mechanism – it works, trust me!
Once that is sorted you’ve got to put the whole lot back together. Fairly simple, apart from the last bit (because the spring is now under tension!). I’ve found that you can use the pedal axle as a ‘jig’ for this. Slot it through the assembly – as if the pedal were together – and then thread the outer bearing nut on to it. Tightening this nut up gradually (using washers / old bearings as spacers) will allow you to eventually force the mechanism back together. Presto – pedal good as new!
It’s actually quite an easy and quick job to do once you’ve figured it out.