Replacement Window for French Doors

Hi all. I am new to this site and was wondering if someone could please help me. :wall: I live in a condo complex that was converted in '73 from apartments. I am currently trying to replace the existing door knob and came to find out that the back set is longer than the standard 2 3/8". It is 3 3/4", yes 3 3/4". Does anyone know where I can purchase a back set of this size????? I can't seem to find the make of the door knob/handle. I bought defiant dead bolt and door knob set to put in. The dead bolt is installed and working, but I can't seem to complete the regular door handle because of the odd back set size. I've already torn the existing door handle apart and can't put it back together. PLEASE HELP :eek: Thank you in advance.

Hi all, I was just curious, I have an inside door to one of the rooms in my house, (it has two exposed screws for the inside plate, and the inside knob slides onto a sort of shaft coming through the door from the outside knob - no threads on the shaft, and basically, my issue is, the screws remain tight, the whole thing is still in place, yet the inside knob just kind of pops off the shaft - I can slide it back on, and the knob will function, but it will pull off again easily - there does not seem to be anything actually holding the knob together? how can i make the knob secure and functional again? I'm kind of lost, here.... Thanks!