2001 GMC Jimmy "round freezer disc" Questions

freezer to shrink it. It was still tight as hell and I can't figure out how to access the adjuster after it is all installed. I would love a step by step description of this process hi from the uk not

...disc, shaped like a rounded dish. You hit it in the center after it is inside the hole, which would hold it it. Another is a cup shape. Again, this kind you would take a socket the size of the inside ...