Firstly,  from your description it do not appear to be ancestral property. 

Your father got this property by a partition among his siblings,  hence even if it was ancestral property,  it lost the ancestral status due to partition. 

Hence your father becomes absolute owner of his share of property,  therefore he has full rights to sell his own property,  his sale of property without the consent of his children is very much valid in the eyes of law. 

Therefore no case to recover the sold property is maintainable  nor tenable 

It is not ancestral property 

2) property which has remained undivided for 4 generations is ancestral property 

3) in peruse terms case division had taken place during grand father lifetime and father received 20 acres as his share 

4) he is at liberty to sell his share without consent of wife and children 

It is not ancestral property 

As the ancestral property was divided by your grandfather and distributed among his sons during his lifetime, the ancestral nature was lost forever. Your father's share of 20 acres became his absolute and exclusive one. He could, legally speaking, deal with it in whatever manner he deems fit, unfortunately. The consent of his children is, again legally speaking, is not at all necessary. You have to face the facts.

The property which your father got on partition became his SELF ACQUIRED PROPERTY 

Upon partition of an ancestral property among the coparcenors the property loses its character of an ancestral or a joint HUF property 

This was not the case prior to enactment of the Hindu Succession Act 1956

However after 1956 any property which a Male Hindu gets on partition becomes his self acquired property in which his children have no right whatsoever 

The Hindu Succession act was made to codify and AMEND the common Hindu law prevailing before that act came into force 

So your father was not at all required to take any consent whatsoever from his sons or his wife 

The sons and the wife will have a right on the father's property only on death of the father provided the properties are not sold by him in his lifetime 

In your case 19 acres out of 20 acres have been sold by your father in his lifetime itself and hence these property will not form part of his estate anymore on his death and will not devolve on his future legal heirs 

The remaining 1 acre if not dealt with already can however devolve on the future legal heirs provided that is also not sold prior to his demise or not bequeathed to anybody by his Will 

Please note when the father is alive his wife and children and not even his legal heirs. They are merely presumptive or future legal heirs. 

Partition brings about an end of an ancestral property 

Had partition not taken place then only you and your brother (and not your mother) would be having a right 

Also despite that your father could very well deal with his undivided share in the non partitioned property in any manner he liked 

The sales in your case have happened over a period of 25 years. Even if you go to challenge them now (provided such challenge is even legally sustainable) it will be considered as a stale claim and will be straight away rejected by the Courts 

Dear Sir,

You can challenge all such transactions by filing a partition suit if you satisfy the following definition of ancestral property.

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What does the grandparent's property law in India state? Does the grandson own the right to the property?

All property's owned by a Hindu person devolves onto his class one legal heir's. 

Now to the specific scenario's in ur example (for sake of convenience I'm presuming ur ur grandfather has only one legal heir)

Senario1: The property is self acquired by your Grandfather, in such case upon his demise interstate (without a will) the property would devolve upon ur Father and not you. In case your farther passes away before your grandfather then it such case it would be devolve upon you, your mother and ur siblings equally.

Scenario 2: the property in question is self acquired by ur grandfather father ( ur great grand farther) - would devolve same as scenario 1.

Scenario 3: the property in question is self acquired by ur grandfather grand father ( ur great great grand farther) - would devolve same as scenario 1.

Scenario 4: the property in question is self acquired by ur grandfathers great grand father ( ur great great great grand farther) - then in such a case you would be entitled to the property by birth as it becomes ur ancestral property.

To give you more clarity on the concept of Ancestral Property's : any property which passes undivided down 4 generations of male lineage is called ancestral property. The right to such property acures at birth unlike other laws of inheritance where right arises upon the death of the the owner.

Hope this brings some clarity to your question and your sense of entitlements.

Meaning of ancestral property  in India-An ancestral property means a propertywhich is devolved upon heirs by the 3 generations above them; father, father's fatheror father's fathers' father. ... That means when a coparcener acquires his share inancestral property than he can make a will to that share and bequest it.

Meaning of ancestral property in India-An ancestral property means a property which is devolved upon heirs by the 3 generations above them; father, father’s father or father’s fathers’ father. It passes to the next three generations.

Meaning of will-A will means a document in which a person specifies the method to be applied in management and distribution of properties after his death.

The basic principle involved is that the property should be four generations old. The right to use and acquire property is accrued by persons through birth itself. The division of property is per stripes i.e. that share of one generation is calculated first than the share of successive generations is subdivided according to share of their predecessor. These basic elements are for governing majorly the Hindus.

If A inherits property, whether movable or immovable, from his father or father’s father, or father’s father’sfather, it is ancestral property as regards his male issue. If A has no son, son’s son, or son’s son’s son in existence at the time when he inherits the property, he holds the property as absolute owner thereof, and he can deal with it as he pleases . A person inheriting property from his three immediate paternal ancestors holds it, and must hold it, in coparcenary with his sons, sons’ sons and sons’ sons’ sons but as regards other relations he holds it and is entitled to hold it, as his absolute property.”[1]

Now answer to the question is that that will to ancestral property is not entirelyillegal. That means when a coparcener acquires his share in ancestral property than he can make a will to that share and bequest it. However will shall be executed after the death of the testator and if the coparcener before acquiring a share makes a will than that will be illegal. Share in ancestral property will be inherited by coparceners. So he can make a will to his share in ancestral property.As whatever he acquires is his share now and he can dispose his assets according to his wishes.

Surender Kumar vs Dhani Ram CS (OS) No.1737/2012 decided on 18th January, 2016 Hon’ble Mr. J. Valmiki Mehta of Delhi High Court ruled-

If a person dies after passing of the Hindu Succession Act, 1956 and there is no HUF existing at the time of the death of such a person, inheritance of an immovable property of such a person by his successors-in-interest is no doubt inheritance of an ‘ancestral’ property but the inheritance is as a self acquired property in the hands of the successor and not as an HUF property although the successor(s) indeed inherits ‘ancestral’ property i.e. a property belonging to his paternal ancestor.

The property acquired by your grandfather from his father shall be his own and absolute property,

Your grandfather had divided the same among his sons subsequently.

Upon such an inheritance your father became an absolute owner of his share of property, therefore he never required to take any consent or permission to sell his own property from his children or his wife.

In the above circumstances the property was never an ancestral property hence you cannot claim any share in it as a right based on your presumption. 

Dear client, 

It is an ancestral property so you have a claim in it. You can file a case in court for your right in the property. Your father will have to pay you back as you were supposed to get and the sale considerations can be borne by your father in the court. Also, the persons who purchased property will have total ownership over that property now so if the sale is legal, you can't claim back the properties but other ways can be sought. 

Thank you 

- As per law, your father was not having any right to sell the ancestral property without taking the consent of other heirs . 

- You can file a declaration and partition suit for claiming the property and to declare the sale deed executed by him null and void. 

- But,  if your father had got those properties after partition of ancestral property , then this will considered as his self acquired property , and he was having his right to sell the property to anyone without taking the consent of any of the heirs. 

You can challenge the said sale deed and recover your share