Might be easier to just pull the clip and install the whole star&cap assembly. I occasionally pull the clip and lock my assembly in the car when I park in risky neighborhoods! I'm not aware of any 'pop-off' stars for the older cars.

Had a front door latch that used to stick OPEN. The grease had dried up and gummed up the mechanism. Freeing up with penetrating oil, then lubing with ATF fixed mine. Maybe, if you remove the little U-shaped chrome latch trim, you can get some penetrating oil inside.

Happy Motoring, Mark

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DrDKW