I managed to puncture the bellows in my RB67 today. Picked it up without realizing the bellows was not fully retracted and puncture it with my finger. Doh! Oh well, it was showing heavy signs of use and cracking, anyway.

I've found a replacement on eBay and it's $75. I've read about cheaper ones, but can't find any. I'm in no rush so I will keep searching for a cheaper solution. Any suggestions?

But I've searched here and Google and cannot find a DIY guide to replace the bellows. Can anyway point me to a DIY or explain in detail how to do it? I've read it's rather simple to do, but no one ever actually says how it's done (not that I've seen, anyway).