Today while working on the cracked butt rib, I noticed something about the hardware that holds the flaps on the hinges.
Each hinge has a “bearing/bushing” where the bolt goes through the Hinge. This bushing protrudes outside and wider than the hinge it self. There is a Felt Washer that goes over the bushing.
P/N 108-8001001 Felt Seal (2 required per hanger)\
Example of what this felt washer looks like new, thanks to https://n9391k.wordpress.com