the grease needs to get into the bearings which go around the sides of the end cap.

The grease goes into the body and is forced out into the endcaps

 

Axle u joints have the zerks on the caps. They are very short so they don't hit anything ever. Normal u joints you fill the middle part, but not on axle u joints.

 

Well I made an *** of myself, but I guess you learn something everyday..............props to Socha_62.

 

Well finally got the joints greased. Just took some back country down on the farm fix it. Turns out there were grease fittings on the endcaps. The way they are suppost to work are place a needle in the hole and this will distribute the grease through the joint. Like I said earlier I was constantly bending and breaking the needles. Gets kind of costly at $4.50 per needle. I finally noticed that there was a groove on the fitting and I tried a screwdriver and took it out. I then used a broken needle in the hole where the fitting went and was able to grease the joint. Like I said probably not the way it is suppost to be done, but it is done never the less. Any way I would like to thank everyone who gave me advice and since I try to do as much work as I can I will probably be needing your advice again in the future.

 

instead of the needle,they also make a tappered rubber tiped end for your grease gun.just remove the threaded plug in the u-joint and stick the rubber tip in the hole.

 

I just had the same problem with mine. some one said to use the needle which like you said would bend or break. after a few went back to the mom and pop parts store (where I should have asked to begin with and not advanced auto parts) They showed me an adapter for a grease gun. It is a metal cone with a really tapered end on it made especially for universal joint grease fittings. kind of expensive ($23) but works great. The guys at those big parts stores wouldn't know what the hell you where talking about, most dont even sell greasable U-joints.