Fluidmaster would like the opportunity to learn more about your installation issue and provide help. Here is a quick tip, the brass bar has cutting tabs so that you can shorten the arm which will prevent it from hitting the tank lid. For additional help contact Fluidmaster’s Technical Service Department, we are available Monday through Friday from 5:30 AM through 5:00 PM Pacific Standard Time. Contact options include: Chat www.fluidmaster.com/support E-Mail techsupport@fluidmaster.com and Toll Free 800-631-2011.