Julian,
Just put the tube of corn head grease into a grease gun and start pumping it in through the fill hole. Should be a 7/16 square head plug on top of the steering box. Just remover it and pump the corn head grease into that hole. Corn head grease is a self leveling grease so it will take a little while to get the steering box full. My steering box took a complete tube plus another 3/4 of a tube, but I had completely cleaned out my steering box. Emptied one full tube and then let it set overnight. Placed the remaining 3/4 tube in the next day.
Hope this helps.
Tim
Last edited by fixit1958; 10/27/2015 3:51 PM.