equal share of Property

Grand father got from great grand father 1/3 share in housr as ancestral property. Therefore his two sons i.e. your father and uncle had shares in the above by birth. Had there been partition immediately before death of grandfather, grandmother and two sons would have got equal share with grandfather I.e. 1/4 each. Grandfather could make will only of his 1/4 share. Rest 3/4 continues as ancestral property in which two sons and grandmother would each have 1/3 share. You cannot file case so long as father is there. Father can file case in case will of grandfather seeks to cover more than his, I.e., grandfather's, share as noted above.

Well the property in question is an ancestral property.. As your late grand father has already mentioned that how the said property is supposed to devolve, what needs to be checked is whether that will is registered or not..if it is not registered then you can easily question its validity.. As the said property in question is ancestral then after raising the dispute you can go for partition.. If the will is a registered one then you are at the mercy of your grand mother..

Technically , there is not much you can do till Grandmother is alive. Although as it seems from your question I doubt the validity of the WILL being a registered or notarized documents or not. Ideally your Uncle and Father should talk across this matter and divide the property equally and file for a mutual division of the property or else you need to wait for the lifetime of grandmother post which the WILL need to be probated.