The biggest reason why Punjabis helped the British during the mutiny of 1857 is that it was Purbias Sepoys (Bhaiya and Bihari soldiers of the Bengal Army) who had fought in the British Army that brought the Sikh Empire of Punjab Kingdom down. The Punjabis felt no pity for their cause as mutiny was started by them.
Another one is that the figurehead of the rebellion was the Mughal “Emperor” Bahadur Shah Zafar II. The Mughals had been the historical enemies of the Punjabis. They felt no sympathy for a cause whose figurehead was a Mughal King.
Guru Nanak Dev -15th - 16th century, the founder of Sikh Religion condemned the theocracy of Mughal rulers, and was arrested for challenging the acts of barbarity of the Mughal emperor Babar and several of the Sikh gurus gained martyrdom at the hands of the Mughal kings.
Dulla Bhatti revolted against Akbar and Shah Hussain - 16th century approved Dulla Bhatti’s revolt against Akbar as; Kahay Hussain Faqeer Sain Da - Takht Na Milday Mungay.
Ninety Years later when India became independent Indian leaders decided to call the Mutiny of 1857 as “The first war of Independence”, which in reality was the last war of Mughals.
Mutiny in British armed forces was encouraged and several hundreds of British women, children were murdered by these mutineers, all over North India. Eighty Years Bahadur Shah Zafar, from the lineage of Mughals, was asked to take up the leadership of the mutineers, which he reluctantly agreed.
During the Mutiny of 1857, the Punjabis sought restoration of the rule of Mughal princes and rulers, and the Marathas hoped to put the Maratha rulers back into power. The princes of the two communities had a unity of purpose in putting up a common front against a common enemy, the British.
Moreover, the situation in Punjab was quite different from the one that prevailed in the rest of India. An important and the main factor was that the Punjabis had nursed a serious grudge against the Bhaiya and Bihari, who despite the Punjabis having never given them any cause for offense, had by their betrayal and other overt and covert acts, helped the British during the Anglo-Sikh wars and later in the annexation of Punjab.
The British used the Punjabi grievance and the consequent “natural hatred” towards the Bhaiya and Bihari. Kavi Khazan Singh in his work, ‘Jangnama Dilli’, written in 1858, mentions that the Punjabi participation against the Bhaiya and Bihari soldiers was in reaction to their boast that they had vanquished the Punjabis in 1845-46 and in 1848-49.
The bitter memories of Bhaiya and Bihari co-operation with the British were so fresh in Punjabi minds that any coalition between the two became impossible. The people who now claimed to be fighters for freedom were the same who, eight years earlier, had actively helped the British to usurp Punjabi sovereignty. On top of that, they were trying to bring back the same Mughal Empire, which over the years had wreaked havoc on Muslim Punjabis, Sikh Punjabis, Hindu Punjabis, above all on Sikh Gurus.
This mutiny led the British to recruit for their armed forces heavily among the communities which had been neutral to this rebellion. Especially, Gurkhas, Rajputs of Rajasthan, Punjabi Muslims and Punjabi Sikhs started enlisting with British forces and were thus back to the profession of their liking, the military services.