The top cables
Chris from NH offers these words:
The conv top drive cables have a 'drive cable' inside them. This inner metal cable does not lengthen or shorten. It is the black cladding covering the drive cable that lengthens due to heat. The newer (replacement) cables supposedly don't stretch/lengthen due to heat. I don't have them, so I don't know for sure - but they're not supposed to. Porsche made this change after a number of conv top failures happened (it was/is quite common on the earlier Boxsters). I'm not sure which model year had the new cables, maybe 2002/2003. The way that you can tell the 'old-style' cables from the new ones is that the old-style have a flat-black appearance (like a Cable-TV cable) and the newer ones have a textured, carbon-fiber-ish look to them.
So, when the cladding stretches/lengthens enough, it stretches *around/over* the drive cable and effectively 'pushes' the inner drive cable out of the conv top cable drive motor. Usually, the left- and right-side claddings stretch at different rates so you'll end up with one side working and one side kind-of working or not working at all.
On the end of the cable (the end that connects to the conv top cable motor) there is a silver 'ferrule' (connector). It is clamped onto the cable's cladding. What you need to do to repair your cable(s) is remove this ferrule (via cutting through and around the cladding below it with an X-acto or other sharp knife - careful not to cut the drive cable, although I don't think you could. Just be mindful of it). Once you have it removed, it will still have a chunk of cladding in it, so you need to remove that. Once that is removed (depending on how much drive cable is sticking out) you will either need to cut more of the cladding off of the cable or just re-attach the ferrule. Re-attaching the ferrule is difficult, but not so difficult that it can't be done. To be honest with you, I tried to re-attach the ferrule and gave up on it. So, it's 'good' to re-attach the ferrule, but it's not 100% necessary. The top will still work fine w/o them. If you want to re-attach the ferrule (and I recommend at least 'trying'), you can use a lubricant that won't harm rubber (like dielectric grease - and this is good to have for other things like spark plugs, battery terminals, etc. - and it's cheap) and try to slide it onto the end of the cable, or you could try heat on the end of the cable's cladding... basically, whatever works. Once the ferrule is back on the cable, you'll want to secure it by pressing in the little metal tabs on the ferrule's collar which 'bite' into the cable. And that's it! It's actually pretty easy compared to installing new cables.
You just want to make sure that once you put the ferrule back on the cable that you have 3/4" of drive cable sticking out past the end of the ferrule. So before you put the ferrule back on, line it up with the cable and make sure there will be 3/4" of drive cable. You don't want to have to take the ferrule off again once you have it back on. Alternately, as mentioned above, don't use the ferrule. Just keep in mind that if you have top problems later on, that one of the cables may have popped out of the motor (although my cables have no ferrules and I haven't had a problem in the 4 years that I've been w/o them.)
After you're done, test the top. But press the conv top button in 1-second bursts so that you can watch/listen and make sure that everything's ok. Once you're comfortable that the issue is repaired, use the conv top button as you wish (but again keep in mind - especially if you don't use the ferrules - that if you hear creaking, or one side of the top is not moving, etc., to STOP pressing the button!) Most expensive conv top repairs could have been prevented if the person just stopped pressing the button soon enough. But sadly, most people don't (me included). : (
Depending on if the conv top transmissions moved independent of each other, you may need to re-time the transmissions. But let's cross that bridge when we come to it. ; )
Let me know if you need help, have questions, etc.
Chris