I have done a lot of these. IF the grommet has the three hoses in. Take out the hoses and it will go in much easier. Even still a bit of oil on rubber helps. Cut hoses on angle to easily fit in grommet, if needed coat hose with oil help here. The one hose needs to go well into take with filter on it. The other two need to just get inside tank a bit like 3/4" or so.