* Screw-on cap with a release lever or button: Many 1956 Cadillacs used a screw-on cap that had a small lever or button on the cap itself. This lever or button needed to be pressed or pushed while unscrewing the cap. The location of this mechanism varied; it might be on the top, side, or even underneath the cap. Look carefully around the gas cap for any small, recessed button or lever.
* Keyed cap: Some higher-end models or optional packages might have included a keyed gas cap. This would require a specific key to unlock the cap before it could be unscrewed. If you have the original owner's manual, it should specify the type of gas cap your specific car has.
Troubleshooting:
* Stuck Cap: If the cap is stuck, try gently rocking it back and forth while applying slight pressure to unscrew it. Avoid excessive force to prevent damage. Using a penetrating oil like PB Blaster (carefully, away from paint) *might* help if it's seized, but be sure it won't damage the paint or chrome.
* Missing Key: If it's a keyed cap and you're missing the key, you'll likely need a locksmith specializing in vintage car parts or a Cadillac specialist to help.
* Damaged Mechanism: If the release lever or button is broken, you may need to repair or replace the gas cap.
Recommendation: Before applying any force, examine the gas cap very closely for any markings, buttons, or levers. A photograph of your specific gas cap would greatly help in determining the correct opening procedure. Searching online for "1956 Cadillac gas cap" with images might also show you examples of similar caps and their release mechanisms.
