Breitling Navitimer B01 Chronograph 43mm - Sunken date wheel modification

[tomtom1009]

Hi,

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.

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 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 and 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.

https://watchesulike.com/en/valjoux-7750/6611-valjoux-7750-date-disk.html













Step 13 : You need to remove all the teeth of the old date wheel, 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 on the new date wheel 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.










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.

 

[cyprusdaedalus]

Duuuuuuuuude i've been looking through posts to see how to do exactly this. Your write up is amazing and so well explained. Gonna have to add a few Breitlings to the shopping list as i've specifically not gone for any of them due to the sunken date wheel.

 

[tomtom1009]

You can perform this mkdification on any A7750 movement.

Before :



Movement modification :




After :

 

[P..DR..D]

Very informative and helpful write up Sir.

Thank you for taking the time to document it:graman:

 

[tomtom1009]

Duuuuuuuuude i've been looking through posts to see how to do exactly this. Your write up is amazing and so well explained. Gonna have to add a few Breitlings to the shopping list as i've specifically not gone for any of them due to the sunken date wheel.

Thanks appreciate that, you can do this mod on any A7750 movement, it’s every time the same constellation ;-)

 

[tomtom1009]

You can perform this mkdification on any A7750 movement.

Before :



Movement modification :




After :

Here another one :

Before:




After :

 

[Ams55557]

Very well done. I was looking for something like this 4 years ago when I started collecting. Without it, I messed up two otherwise perfect movements as a novice.

Now, 4 years into the hobby I realize that this guide back then still wouldn’t have helped me. At all. Zero.

I’ve built…20..30 watches and am very confident that while I’d be able to handle most of these steps, there are 4 steps which require an amazing amount of capacity. Anyone who isn’t a pro or who would identify as naturally gifted jewler is guaranteed to mess up one of those four steps.


So, if you are coming here new, or you are me coming in 2025 wanting to mod that DSOTM or something…don’t. Just….don’t. This is hard stuff that takes a lot of skill. Dude, Just pay someone to do and not break perfectly good things you (I’m) not even close to being this good.

 

[tomtom1009]

Very well done. I was looking for something like this 4 years ago when I started collecting. Without it, I messed up two otherwise perfect movements as a novice.

Now, 4 years into the hobby I realize that this guide back then still wouldn’t have helped me. At all. Zero.

I’ve built…20..30 watches and am very confident that while I’d be able to handle most of these steps, there are 4 steps which require an amazing amount of capacity. Anyone who isn’t a pro or who would identify as naturally gifted jewler is guaranteed to mess up one of those four steps.


So, if you are coming here new, or you are me coming in 2025 wanting to mod that DSOTM or something…don’t. Just….don’t. This is hard stuff that takes a lot of skill. Dude, Just pay someone to do and not break perfectly good things you (I’m) not even close to being this good.

You’re right, for me there are three steps you have to do carefully otherwise you can mess up your watch.

It starts with the removing of the hands from the dial (step 5 and 19), if you don’t use the right tool or pay attention you can easely bend or scratch the fragile hands.

Then the tricky part is the alignement of the date and the date wheel teeth of the old and the new date wheel so that the date is centered correctly in the date window (step 14).

For me the chalanging part is the trimming of the wheel number 3 where a false move can destroy the wheel an so you loose the 3 o’clock subdial (step 17).

Otherwise the rest of the steps can be easily done.

By the way, I’m not an jewler nor a watchsmith ;-)

 

[Ams55557]

By the way, I’m not an jewler nor a watchsmith ;-)

Ahhh. Yes. But you have the natural gift. If you have the gift you have the gift.

 

[Akilles]

Great tutorial. I thought of doing this on my old Navi-rep but glad I didn't after reading this. I would have more success trying to build a space rocket than fixing all those steps without breaking the watch.

I went another path instead. Nice to see that some still like the Navitimer!

 

[tomtom1009]

Great tutorial. I thought of doing this on my old Navi-rep but glad I didn't after reading this. I would have more success trying to build a space rocket than fixing all those steps without breaking the watch.

I went another path instead. Nice to see that some still like the Navitimer!

Good choice, it’s a beautiful watch


Sent from the RWI App

 

[Ams55557]

Maybe a silly question. But why do you need to do step 17?

without having the half gear there, what would the problem be?

 

[tomtom1009]

Maybe a silly question. But why do you need to do step 17?

without having the half gear there, what would the problem be?

Without step 17 you have no pin @3 o’clock for fixing back the chrono hand because on the A7750 there is originally no subdial @ 3 o’clok, it’s moved from 12 o’clock to 3 o’clock by the three supplemental gears.

You can see on the third picture of step 15 that there is no pin to put the hand back.

 

[tomtom1009]

Here a daylight picture of the end result

 

[Ams55557]

Ahhh. Ok. So the wheel is just the pinion and there is no specific spot to cut the gear. Ok that’s less of a big deal.

 

[fsucrzy]

Great tutorial! Unfortunately I do not have surgeons or jewelers hands - I’d muck this up for sure! Ever thought of offering it as a service???

 

[AstroAvia]

Congrats on the courage and nerves to do that mod, which significantly improves the looks of the watch.

I am an old-timer here and have modified several of my own watches with this mod, like Hublots, IWC, Bulgari, Corum, and I managed to keep the chrono functional on all of them.

Rather than bragging, my post goes only to say it is possible to keep a functional chrono minutes counter. Also, allow me to correct one aspect of your otherwise very informative tutorial: the datewheel to have its teeth removed is the top one.

 

[AstroAvia]

I stand corrected! I reread your text and have just realized that you used the replica DW on top! I am not a Breitling fan (well, not a Navitimer fan for that matter), so I don't know if the chinese date font would be more accurate than the swiss. Anyway, I would have installed the swiss DW at the top, and that's what I did to the watches I modified, given that all their gen counterparts use the standard swiss 7750 date font.

 

[TBK]

I knew this mod already, but never saw such a good write up of it. Well done! thanks tomtom1009

 

[Eptruong]

Is there anyone that can do this for my Breitling Navitimer B01 With a white date at 6h? I will pay for all parts