Hook ends.

[Tweegs]

OK gents, having a heck of a time with these things. On vacuum I don’t think it would be a problem, but on gravity I think I’m going to get some grief.

Problem is that the tension from the lateral line is causing the hook end to pull towards the tree. This causes the hook end to want to roll around the mainline slightly which puts an upward tilt on the tube between the hook end and the saddle.

I’m going to try to put wire ties on either side of the hook end to give it more support. Short of that, anyone got another idea?

[WESTVIRGINIAMAPLER]

I use "Y" forks for all my lines where they come into the mainline. There is almost always a tree of some kind next to where you bring it into the mainline or might have to move it a little to the right or left where you bring into the mainline. Using the "Y" fork, you can use old good for nothing else tubing around the tree as the sap flows straight thru the center. I used to use the hooks, but I like the "Y" forks much better as there is no tension on the lateral line and if something falls on the lateral line, there is no stress of any kind put on the mainline. Cost a little more but well worth the extra.

And besides, most importantly for you, it eliminates all the problems you are having.

[Squaredeal]

This can be a problem with vacuum too. If the tension is great enough to cause the fitting to not be parallel to the lateral line it can cause a slight vacuum leak -you can't hear it or see it, but it's there. It also forms a weak link where the lateral can come apart if (when) subjected to stress.
I have found the IPL flat hook connectors to be far superior to the leader connectors. The hook on the leader bends out of shape almost immediately after being subjected to tension. The IPL fittings retain their shape over time and the barbs are further apart and seem to hold better.