The Marathas wanted to depose the Mughal Emperor during the Maratha-Afghan war (the 3rd battle of Panipat) and crown Viswasrao (the son of the Peshwa Balaji Bajirao Nanasahib) as the Emperor.
I got this information from the book "Islamic Renaissance In South Asia (1707-1867) : The Role Of Shah Waliallah" by M.A. Ghazi , where it says :
"Some maratha chiefs tried to place a young lad of seventeen, Vishwas Rao, the son of the Peshwa, on the throne of Delhi to proclaim the realization of their long cherished dream of Hindu pad padshahi"
If it is true, then why would the Marathas want to crown their leader's son instead of crowning the leader himself? Also, if they succeeded, what would their administration look like — where the Peshwa's son would act as superior to the Peshwa himself?