My '56 Victoria broke a window roller.  I ordered a bunch of new ones on the internet.  Fit fine, looked like perfect replacement part.  Twice now, the rollers have jumped out of the track and the window falls down when the door is slammed.  

QUESTION:  Are there different sizes of these rollers and how can I find the proper size (slightly larger than the ones I have now)

It’s been several years, but I replaced the rollers in my 55 bird, parts from Larry’s Thunderbird. Alway had good luck with Larry’s. One broke and failed in probably 30 cycles up and down. Replacement was fine. So it might be a bit of a crap shoot, hard to tell with 1 out of 4 being the sample size.

miker
55 bird, 32 cabrio F code
Kent, WA
Tucson, AZ