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they dampen...but dont rebound
They won't unless they're gas... and they're not. You'll have to manually rebound which is almost impossible if they are on the hardest setting.
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are these the "old school" koni's where you have to compress them to adjust, unlike the new ones with knobs on them?
Probably, I believe all Konis are adjustable (at least all the ones made for those struts are). Push them down all the way and turn the shaft until you hear/feel a click. Turn completely counterclockwise (me believes) to bring them to full loose. You should be able to manually rebound them in that configuration.
Check for leaks, otherwise they sound like they're in fine shape. Check out www.konina.com for an address. I believe they'll revalve them for $55.00. I know quite a few people that use the 911 inserts in 914's. In fact, they (Koni NA) were a little clueless when I called about the same thing. You may have to dig deep in the CS department to find someone who knows what you want.