They actually aren't vulcanized on, but merely press fit into place. Very tightly press fit.
Over the years, though, they tend to stick themselves pretty good to the a-arm.
They are easy to remove if you heat them up real good. You can remove with very little force. But if you could apply enough force to them, you could get them removed without heating them. And you might be able to do it without damaging them.
But getting them removed isn't the problem.
The problem is getting them back on.
You can buy stock rubber style bushings from places like Smart racing. Some have tried that. But the problem is getting them on. When you see the size of the uncompressed rubber bushing, you quickly see the problem! You'd need some kind of huge press, and probably some tooling to get them started without destroying them. Smart Racing does it somehow, but no one seems quite sure how.
(P.S. Pete S. - See, this is information people need! Let me know how it's going
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