Most drillers would drill out the crack, plug the fingers, and redrill.  That's the best cure.  I have fixed a couple that were around 1/16" wide by using tape inside the finger holes to keep the crack from leaking and form part of a dam around the bridge, then pouring plug material into the crack.  I haven't had one of these come back.  But do something before the crack gets worse,  --  JohnP