I had an interesting install of greasable U joints. The one I got had what seemed to be a needle port on the end of one of the caps. Well, I had a grease needle, so I stuffed it in and gave it a shot. It came right back out the port, didn't seem to accomplish anything. Then I broke the needle off inside.
Oh, it gets better. Round 2:
I recently got some experience installing zerk fittings. It seemed very logical to drill out the hole where the needle port goes, thread it, and put a zerk fitting there instead. I know a zerk fitting will work, I understand them.
I pretty much destroy every drill bit in my shop trying to make that hole. Apparently, U-joint caps are made out of very hardened steel. I am past the point of return with the needle port, so I forge ahead. Somehow, I get to the final drill size... oh wait, I forgot part of the nightmare.
I was doing all this after I had pressed the u joint into the yoke. And then I busted a drill off inside. So, I had to get it at least to the point where I could get the cap off.
Ok, I get to the right hole, and with a high-zen state of patience, I tap the threads, 1/4-28, I spend 30 minutes and back the tap out often. Good. I clean out the filings and insert a zerk. ( I bet you were expecting me to break the tap... I was sure I would, but I lucked out.) Nice! I pump some grease in and it peeks out the seals, good. It does what I want.
I put the axle back in. Whoops. The zerk hits the edge of the hole in the knuckle. I sort of expected this and figured I would cross that when I got there. I ended up removing the zerk and stuffing the axle in. I look at where the zerk would go, and the clearance is really tight. I can see myself knocking off the zerk during the winter, which would be just bad. So, instead of a zerk, I threading in a shallow set screw with some blue threadlock. So, to grease, I remove the set screw, thread in a zerk, and I am on my way.
I will not do that ever again. I will have to learn how the needle grease port deal works, or I will go with permanent grease models. I will never attempt to drill a hole in a U joint cap again. Unless you have carbide tooling and a rigid drill press, I would advise against it.
