• Tired of adverts on RWI? - Subscribe by clicking HERE and PMing Trailboss for instructions and they will magically go away!

HOW TO - A7750 sunken date modification

tomtom1009

You're Saying I Can Sell?
21/8/20
88
151
33
Hi friends,

I recently bought myself an GF Breitling Navitimer B01 Chronograph 43mm with an A7750 movement and a black dial on a black leather strap from Hont.

http://www.hontwatch.ru/index.php?main_page=product_info&cPath=32_145&products_id=9142

The watch is very beautiful and one of my favorite watches so far, but the sunken date wheel bothered me a lot.





After some researches on RWI and Reddit, I read that some people already successfully performed an modification to correct the sunken date wheel issue.

from ''onzenuub'' @ rwg.bz

I'm not an watch smith but I decided to give it a try and to see if i could do it myself without ruining the watch so bought some equipment from amazon to perform this operation.



Here you can see how sunken the date is before the operation.





Now I'm going to do a step by step tutorial for those who like to do the same on their watches.

Step 1 : Take off the strap of the watch.



Step 2 : Remove the back cover with the right opening tool.



Step 3 : Remove the movement from the case by losing the three screws.





Step 4 : Remove the metal spacer ring from the movement by losing the three screws.



Step 5 : Remove the hands of the dial, you need to be very carefully not to scratch or bent the hands.





Step 6 : Remove the dial from the movement by releasing the the two hooks on the side of the movement.



Now you can see why the date wheel needs to be so sunken, it's because the transfer of the sub dial from the 12 o’clock position to the 3 o’clock position needs 3 more gears.

Step 7 : Remove the metal plate hold in place by two screws.



Step 8 : Remove the three wheels, it's important to keep the wheel number 3 but the wheel number 1 and 2 are not needed anymore.



Step 9 : Remove the two plates hold in place by three screws and the spring with the lever of the date wheel.









Step 10 : Remove the outside ring of the movement hold in place by three screws.





Step 11 : Thake the date wheel out of the movement.



Step 12 : To raise the date wheel I bought a new Valjoux 7750 date wheel from the internet which is going to be placed under the old date wheel.

Link








Step 13 : You need to remove all the teeth of the old date wheel (the one you're putting on the top), but before you do so, you need to memorize the position of the teeth and the date font so that you can align it on the new date wheel.









Step 14 : Now you need to glue the old date wheel (without the teeth) on the new date wheel (with teeth) and align the date font exactly with the teeth of the new date wheel.





Step 15 : Put the date wheel and the outside ring bock in the movement and put the dial back on the movement to check the height and the alignment of the date.








Step 16 : Now you need to put the wheel number 3 back in place, but now it doesn't fit because of the risen date wheel.



Step 17 : You need to modified very carefully the wheel number 3 so that it fits beneath the raised date wheel by cutting one half of and gluing it into the movement.







Step 18 : Now you can put the plates in place on the movement and check the date wheel change.



Step 19 : Put the dial and the hands back on the movement.






Step 20 : Put the movement back in the case an attach the strap.






Done.

Here you can now see the before and after photos :












The only downside of this modification ist that now the 3 o’clock sub dial is frozen.

I’m very happy with the end result and the watch is now perfect for me.

I hope this tutorial can help you out th perform this mod by yourself :)

Thx.
 

tomtom1009

You're Saying I Can Sell?
21/8/20
88
151
33
I also successfully performed this A7750 mods :

Breitling Navitimer 2022

After :



 

Pinion Minion

World Class Breaker of Movements
Supporter
Certified
5/8/22
1,957
5,788
113
Texas
Fantastic write up!!!

Thanks! A great contribution to the RWI knowledge base.