Here you can see the newer plunger above and the broken one.
The kits now also contain an extra washer that some are using for an unusual technique which is again putting unusual stresses on the Makin's and one would be better off using the stainless steel extruder for that. Also it could make your warranty void by using in a way than otherwise intended. But I digress. This topic is on fixing or making your broken extruder usable. While I do have a new extruder I had orginally kept the broken one just in case I needed the barrel, or whatever other part. I now use my broken extruder for dark clays and the newer on for lighter colours.
You could also use your broken extruder for unusual techniques instead of risking your good one...