thx to IFIXIT and 20+ years of computer repair and building experience (all PC) there was no problem at all to remove a 500 Gb HDD from a mid 2011 iMac and replace it with an 500 Gb SSD Drive (with help from Comtec EDV, where i bought the upgrade kit).
Skip the steps where people are advised to remove the display. Due to my experience it is def better to leave cables and plugs where they are. I lifted the display 12 cm and fixed this position w/ one pencil in each front corner of the case where the other end of the pencil sticked in ascrew hole of the display-frame. Very easy to operate afterwards! No probs w/ the screws of the hdd-frame.
Some care-taking of static electricity is advised - wear a wrist cable. And don’t forget to press start button after having removed power chord. I had an Android Tablet on the right side, where i could watch these ifixit pages :-)
thx to IFIXIT!
w/ regards from cantbtroo from Berlin
Btw, I was pretty safe (& content) with two suction cups - i bought 3 for less than 7 Euros. They were a good help for a glass that hasn’t been removed since 2011. But i am sure fingernails will do a good job, too (of course not mine, cos i have short ones).
At the end of the job it was even possoible to clean the fan that sucks cool air into the iMac (w/ a paintbrush and a controllable vaccuum cleaner). After that, it’s also a good opportunity to clean the air inlet that is part of the aluminium case (behind the stand - it’s always dusty).
w/ regards from cantbtroo, Berlin