If you are meaning the grease zerks, they are 1/8" pipe thread. 27 threads per inch. Some are straight, and some are 90º. Unless the zerks are terribly beaten, or battered, it's probably dirt packed in the hole below the zerk. Remove the zerk, then clean the hole with something like a small flat blade screw driver. In the field, I filled the hole with penetrating oil, replace the zerk, then pump grease in. Most grease guns produce close to 12,000 psi, and will push the dirt out with the penetrating oil, and the grease will follow. You may need to hold pressure on the grease gun handle for a bit, but it will go, unless the bushing has spun over the grease hole.
I don't know if you've found it yet, but there is a grease zerk on the front hydraulic pump drive shaft u-joint. Those wiley Ford engineer's put it in a real tight spot to get to. Our mechanic ended up cutting holes approx. 6" X 8" in the lower front cowling to make it a lot easier to get to.
