From a safety point of view stop using it.no way of repairing you have to replace HOWERVER sometimes the glass tops cost as much as a new hob.Sorry
ck
January 2012
you dont say if the crack is over the hot rings, or were the crack is, if the crack, is away from the heat, you might be able to seal it , to keep the water from spilling down into the body, or how ling the crack is? its all about safety,,