I'm using a needle adapter to grease the front u-joint on my rear driveshaft, because the driveshaft is in the way of getting the head of the grease gun over the zerk. I can't press enough grease into the joint with the needle adapter to get it to ooze out (not through the zerk), so I'm not confident that I'm pressing enough grease in to lube it effectively.

Can anyone reassure me that needle adapters get enough grease into a zerk, despite their inability to apply the ammount of pressure that you get with a standard zerk-gun coupling?

In case the needle adapter really is inadequate, I'm considering a couple other options, which are open for comments.

Remove the joint every time that I grease it.
Remove the zerk and replace it with an extended one, if I can find one long enough.

 

Well, I have to use a needle adapter on my lower ball joints becasue I can't get to the zerk without unbolting stuff, and it seems to work ok. Not as much grease will fit through the needle, so you might think you have put in more than you actually did. Also, check to make sure there is actually grease coming out of the needle.

Other than that, just keep squeezing, it'll fill up eventually...

 

It fill up allright, it just backs up out the zerk rather than beeing forced through the joint.

 

So you don't have enough room to get a fitting on the zerk, can you take it out and use the needle in the empty hole? Usually needles are used to pierce a rubber boot and inject grease that way, not through the zerk... but this doesn't really work with a u-joint obviously.

 

I've got one... it's not really a needle, though (at least it's different from the ones used to pierce boots for greasing.) The tip is shaped so that it forms a seal with the hole in the zerk fitting when you hold it against it. It works fine for me... I'm able to get grease to come out through the U-joints.

This would be helpful for you. Scroll down the page until you see this adapter: ST-8034 - Right Angle Grease Coupler.

 

You're right, I shouldn't have called it a needle, it's more of a cone. The tip of it fits against the end of the zerk, pressing in the ball. The pressure that forces grease into the zerk is limited by the force with which the gun is held against the zerk, since the two don't exactly couple.

I wonder why you're able to get the grease to come out of the joint, while I can only get it to back up through the zerk. Maybe there's hardened old grease in the way. It might take more pressure than I can hold to press that stuff out. Hmph. Maybe it's time to take that joint off.

As for the right angle grease coupler, I don't think it'll work. The problem isn't that the zerk is pointed toward an obstruction, it's just that there isn't enough space around it for the grease gun's coupler. A very thin-walled coupler would do the trick.

 

It's been a few thousand miles since I've crawled under the truck to look at the driveshaft... I thought there was access to the zerk from the side as well (which is what you need for the right angle coupler). I could be wrong.

In any case, there are "thin walled couplers" that do fit in to mate to the double carden joint zerks. My old grease gun had one and I had no problems accessing any of the zerks. When I bought the new one, it had a thicker coupler, and I ran into the same problem as you, which is why I bought the "needle" adapter. It's worked great for me since.