I have a Hoover U4063 model and I can't remove the brush bar to remove the belt. How do I do that?

I have a Hoover U4063 model and I seriously need to change it's belt. It's easy to access, however, removing the brush bar is my problem with this model. I need to remove the brush bar to get the belt off and I don't know how. I'm usually a do-it-myself kind of person, but as this is the only vacuum I own, I'd rather not break something in the attempt to figure it out myself, considering this model is over 40 years old.