I use a plastic syringe and a length of tubing. Remove the "zerk" fitting on the end plate covering the spindle and hold the tubing to the opening while injecting 140wt oil (NOT grease) into the spindle. I usually remove the rear wheel to gain access to the 1/4-28 bolt which locates the spindle. Remove the bolt and fill until the oil seeps out this bolt hole. Replace the zerk fitting, then replace the spindle locating bolt and the rear wheel.