Auto Zone Compass & Mounting Bracket The car compass failed. The magnet fell off and this released the card from the pivot. I found an inexpensive compass at Auto Zone. One could pop it apart with a knife blade. I discovered that the compass has a rubber diaphram in the bottom surface to accommodate pressure changes. The black plastic parts were discarded, and a hole was cut in the mounting bracket to match the rubber diaphram position. The compass was glued to the mounting bracket and attached to the windshield.