Replacing Weatherseal 55-106

I want to replace the weatherseal on all of my wood casement windows. I matched the product to 55-106 and this should work great. However, the old weatherseal has brittle, hard and cracking. When I tried to remove the old seal, everything broke apart except the piece that fits in the groove. This is still fairly 'elastic' and I am having a hard time removing it. Any suggestions?
Thanks!