Hi,some can be replaced easier than others. If it is a wedge type gasket it's pretty simple and you won't need to take the units out. If you're problem is that they've shrunk you can just pull out each end stretch them and glue them back in to stop them from stretching back.
DIY how to tutorial projects and guides - Did you know we have a DIY Projects section? Well, if no, then we certainly do! Within this area of our site have literally hundreds of how-to guides and tutorials that cover a huge range of home improvement tasks. Each page also comes with pictures and a video to make completing those jobs even easier!