Anderson split, Plastic piece broken on bottom of block

Take a look at our 39-146 and 39-147 for the Split-Arm Operator. See if this matches the dimensions of your old hardware. I am afraid the window balance looks like a jambliner system, which we cannot replace; but if you contact your nearest millwork, I believe they should be able to help you. I apologize we can't be of more help, and many thanks for considering our business.