47-55.1 Rear cab rib asphalt

[8man]

Ok, the title is confusing, but I was looking at the 3 ribs in the back of the cab that go from the floor up to the window area. One of mine is bent in, toward the cab, and there is some type of old asphalt coming out. The other two have the black asphalt stuff too, but it's not falling out where I can see it.

I have a rib to replace the bent one, but I'm wondering what material are you putting behind the ribs? How do you get it behind the ribs if they don't need to be replaced?

Thanks.