I often make purchases from agri outlets. Don’t go to the ‘computerised’ spare parts desk as your first choice – many smaller, local agricultural engineers are often a better bet. Many bods behind those ‘parts computers’ are just that – computer bods.
I am lucky in that a friend runs an agri-business and I help him out occasionally.🙂. He buys in lubricants, anti-freeze, batteries, etc in larger sizes/numbers.