Exhaust hangers suspend the exhaust pipes and muffler from the frame. They are made of heavy-duty rubber. This rubber keeps the hot exhaust from rattling against the metal body. It also allows the exhaust system to expand and move as it heats up.
Rubber hangers get brittle from heat cycles and road salt. They tear and drop the exhaust pipe. A dragging pipe will scrape along the ground, causing holes and expensive leaks.