Left Coast Guy 24 Posted June 1, 2014 I'm replacing the movement in a Breitling Navitimer Worldtime with GMT hand, and am looking for some help on any mods I'll need to do to a standard 7750 Movement to get the GMT hand to work. In disassembling the original movement, I found there was an overlay wheel and pinion (connected) that held the GMT pinion and rested on top of the hour wheel. The hour wheel had two notches on its top connecting it to the hours wheel. See picture below: In the holes on top of that GMT wheel, you can see the pins where it is connected to the hour wheel. So my thinking is that if I just disassemble the replacement 7750 to the point of replacing the hour wheel, I can insert this hour wheel and gmt wheel and by good to go, right? Or are there other mods I'd need to do to get the GMT function to work properly? Share this post Link to post Share on other sites
SSTEEL 0 Posted June 1, 2014 It is possible yes, you need to change the movement plate over too with the cut out for the gear pinion that drives the GMT pinion. Share this post Link to post Share on other sites
Left Coast Guy 24 Posted June 1, 2014 Thanks, Micky. May drop you a note when I get to that point. I've got the parts from the broken movement, but haven't found a guide on line for reassembly of a 7750 with GMT, so not 100% sure what parts need to cut over. Share this post Link to post Share on other sites
SSTEEL 0 Posted June 1, 2014 I have some A7750 GMT movements, give me a minute or ten, and I will get a photo of the GMT components from one I'm working on right now. Share this post Link to post Share on other sites
SSTEEL 0 Posted June 1, 2014 A7750 components.. 7750 GMT components by Micky.!, on Flickr SANY0060 by Micky.!, on Flickr A assembled A7750 with GMT.. SANY0062 by Micky.!, on Flickr SANY0063 by Micky.!, on Flickr Two A7750 movements with GMT removed.. SANY0061 by Micky.!, on Flickr Hope that helps. Share this post Link to post Share on other sites
JSJ 0 Posted June 1, 2014 That's brilliant Micky, and I don't even have a GMT 7750. Really great to see it so clearly. Thanks. Share this post Link to post Share on other sites
Left Coast Guy 24 Posted June 2, 2014 Wow, thanks Mickey really appreciate it. I still haven't got my replacement movement in the mail yet, so driving me crazy to see this and not be able to work on it! I've got all those parts, and fair certain how to install, except for the top-shaped gear just above the GMT wheel in your pictures. What is that? Where does it go? Share this post Link to post Share on other sites
