You can reuse that "gasket", or eliminate it, since it is just a spacer in case the tank tightens far enough so it comes close to the bowl. The toilet will work fine either way, as long as you replace the round center seal. If you do reuse it the "U" goes towards the rear of the tank.
The closed end goes to the back of the tank. Are you sure you used the right tank to bowl gasket? There are different types. Compare the old one with the new.
John
when you installed the bolts did you put the rubber gaskets under the bolt heads, or did you install metal washers first? Normally I would install nuts on the bottom of the tank to secure the bolts, but that model does not have enough room to do that. And if you DID use nuts on the bottom of the tank, that is why it is leaking because it does not compress the rubber gasket properly.
This is awkward, but...
It looks like you're using an ad blocker. We get it, but (1) terrylove.com can't live without ads, and (2) ad blockers can cause issues with videos and comments. If you'd like to support the site, please allow ads.
If any particular ad is your REASON for blocking ads, please let us know. We might be able to do something about it. Thanks.