I am surprised I have not been able to find some info on how to fix this. The glass is popping out of the plastic frame at the bottom. I think it's held at a bit of tension because simple re-setting it into the groove does little as it pops out again.

I assume I need to probably do a full removal/cleaning/reattachment, However I have no idea what products to use or if I will need some of those suction windshield holders.

Does anyone know of a DYI document or site to tackle this?

I found some videos online but they are for R57s which don't use the plastic frame.

 

There is a tool for tightening and adjusting door windows:
Amazon has one for $30, but you can find them cheaper on the site or Ebay and some local auto parts dealers!

 

The OP is referring to the rear window of a convertible roof.

In the videos you found for the R57, the owner improvised a fix using available products. You'll need to try as well, using similar adhesives and sealants.

The official MINI/BMW service manual (used by dealers) have no instructions for servicing the rear window (both R52 and R57). A dealer would replace the entire soft roof, which comes with a window bonded to it:
https://www.newtis.info/tisv2/a/en/r...le-top/ER1sNR0
https://www.northamericanmotoring.co...g-unglued.html
https://www.northamericanmotoring.co...placement.html

 

It really sucks that you can't just buy a replacement window. If it were ever to crack it would cost about $3K to fix instead of a couple hundred bucks.

I think I will try some strong silicone adhesive. I am glad it's not an R57 or later where you have to adhere the canvas directly to the glass, which sounds like an absolute nightmare.

 

Other the regluing the top to the fabric, which they posted above, it requires a new top. I guess you could try with the insurance company?

https://www.northamericanmotoring.co...w-rag-top.html