Can vaseline be use like a lubricant on o'ring for pump?

Yes, Vaseline can be used as a lubricant for O-rings in pumps, as it provides a good seal and reduces friction. However, it's important to ensure that the Vaseline is compatible with the materials of the O-ring and the fluids involved. For applications involving certain chemicals or high temperatures, specialized lubricants may be more appropriate. Always check the manufacturer's recommendations for the best results.