This might be a newb question and something already answered and I just can't find the answer but I'm changing the fuel filter and oil/filter for the first time since buying my cruiser. Its a 1979 BJ40. When replacing the fuel filter, do I need to prime the fuel lines going to the filter or just fill the filter with diesel? both? I don't want to do anything wrong to hurt the motor. Ive never worked on a vehicle this old so its all new to me.