I have a 900D case and I seem to be having 2 problems that may be separate, but they may be related.
1. The lower door on the right side(on the side with the window). When opening and closing_ the door appears to be stuck. It feels like the contact is metal on metal so I look inside the case where the hinges are located and they appear to be making contact with the basement floor of the case. There is nothing that I'm seeing anywhere that could be causing an obstruction. If I use a small bit of force with my hand, I can close and open the door completely. This is annoying, but its not the end of the world. I would like to know what the problem is so I can fix it if possible.
2. The brackets on the bottom side(on the side with the window). My goal here was to install 4x 120mm fans. Now_ I noticed the extra brackets screwed to the bottom of the case. I took those off and I figured out how to install the top bracket, no problem. The lower bracket is where I am having an issue. The hooks on the bracket appear to match up with the slots the bottom of the case. Now when I attempt to slide the bracket into place, for whatever reason I'm not able to align the hole on the bracket with the hole on the bottom of the case. I'm certain I have to slide the bracket because when I line up the holes, then_ cross reference the top bracket, all of the 140mm holes match up.
I've included pictures. I don't know how I would go about ordering new brackets if circumstance say I would need them(I shouldn't).
I've reached out to different forums and after looking at my case again, I have new information.
Issue 1: Solved. Thanks for the help. I turned the case on its side and I was playing with the bracket again and I lined it up just like I tried before and not even thinking, the bracket slid_ and to my amazement the holes where you put in the screw actually lined up. Maybe I wasn't applying enough force to slide it in place, but I turned the case on its side and the holes where you place the screw for the bracket lined up.
Issue 2: I'm still having an issue. I check the bottom of the case, turned it sideways and upside down; there were no loose screws or anything inside. I did a visual check on both hinges on the left and right side of the inside of the case and both of those cleared. I have the case on its side right now and I'm trying to ascertain the exact location the noise is coming from when I try to close the door. When I open the door now, it feels fine opens completely like normal. Its just when I try to close it, I'm trying to find where I am facing resistance. I will just nudge the door from its open position and see where it stops about half way_ to fully closing. The case is large, so let me check again, there may actually be a screw. The case is pretty large, I have to wrap my arms around just to turn it over.
Update: I just checked again and I believe I've found the point of contact between the door and the case. I triple checked for loose screws, nothing there. Apparently, in one of the holes that connect to the metal door(the solid piece of the door that I took off that normally covers the dust filter). On the bottom/farthest to the left slot of the vented door_ that little hinge/lock piece of metal appears to be making contact with the case right when the door stops. I bounced the door a few times to confirm and there were scratch marks on that piece of metal. Once the door cleared that part, it closed perfectly fine. I've taken some more pictures, so you can see where I am visually looking.
In conclusion: I believe the vented door on my particular case on the lower right side with the window_ has a defect. Oh well, its not a problem. I'm just happy I figured out the issue and that it wasn't something that resulted from my tinkering with the case itself. I can live with it.
Thank you very much for your help!