I bought a new one last year on eBay. Did Pelican Parts have it?

And yes the Plastic Ball can crumble away but more frequently the inner part pulls out of it. A less frequent failure area is the rubber part.

Other years and models may have different types.

People keep speaking of 3-D printers. Perhaps another type of plastic will work.

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84 300D, 82 Volvo 244Gl Diesel