Service: Zenith Zenith Class Elite Reserve De Marche 18.1125.685 calibre 685

This Zenith came from London, and it’s not been serviced since it was bought new 11 years ago.

What strikes me are the bits of dirt on the dial – click on the photo to enlarge it, and you will see what I mean. Check around the 1, 6 and 11 o’clock markers.

The case has a sapphire crystal, as you want to be able to see the 22k gold rotor.

The amplitude is very low, and the movement runs 2 minutes per day slow. Definitely time for a service, and after 11 years, no wonder.

A first look at the calibre 685, which looks very nice indeed.

The dirt on the dial cleaned up nice enough, but I have no idea how it got there! It looks like the stuff you find between the spring bars after years of wear, and definitely isn’t anything that has come out of the movement itself. The only explanation is that the watch has been opened up at one point, and the case back definitely shows signs of an opening prior to me opening it.

The bottom side of the movement with the date disc.

The movement taken out of the case.

With the rotor removed, you can see the wheel that transmits the rotor movement to the auto winder gears.

From there, it’s on to two reverser wheels, onto another 2 intermediate wheels, and finally to the ratchet wheel on top of the barrel.

From the barrel, the gear train on the right is driven. The octopus-like spring at the top of the barrel is the hacking lever.

The hacking lever in all its beauty.

The gear train from barrel to escape wheel.

This made my head explode a tiny little bit upon first looking onto it. The pinion on the left is driven by the gear train, so as the movement winds down, it turns the three wheels to the right of it, and finally the outer wheel of the satellite gears in the middle, and thus turning the power reserve indicator towards 0. The inner core of the satellite wheel is driven by the barrel arbor, so when the watch is wound, it turns, and, through the inner satellite wheel, will drive the wheels to the right of it, this turning the power reserve indication towards “wound”.  Note that the wheel to the right of the inner satellite wheel has a clutch on it, so it can slip. You can also see the last wheel at the top right, with a heart-shaped cam, and a spring that presses onto the cam.

The satellite wheel opened up. The inner wheel is driven by the barrel arbor, and the outer satellite wheel is driven by the gear train. The inner large wheel drives the power reserve indicator.

Below the power reserve indicator level, the date mechanism with a quick-set function lies.

The date wheel driving the date ring.

You can see from the amount of parts that this is no simple movement.

Assembly starts with the cleaned mainspring going into the barrel, with a bit of braking grease on the barrel wall.

Then the balance jewels go in.

The gear train and auto winder train in place, with the movement ticking.

The movement isn’t fully wound yet, so the amplitude is still a bit on the low side.

Now I put in the date mechanism…

… and then the power reserve gears. You can see the whole mechanism now in its full glory, and this has to be the most complex power reserve indication that I’ve seen so far.

The hands go onto the cleaned dial.

The movement cased.

And voila, ready for testing. The power reserve hand goes from 55 hours when fully wound to the last red marker when fully wound down. During testing, the watch actually has 56 hours power reserve from fully wound.

The complete set of photos is here.

Addendum:

For those seeing fibres:

21 thoughts on “Service: Zenith Zenith Class Elite Reserve De Marche 18.1125.685 calibre 685

  1. The complete set of photos is excellent! Thank you!
    I am about to overhaul my Zenith Cal. 682, so it is good to know in advance what´s below the dial and bridges.
    I recently already serviced a mainspring barrel of a Elite-calibre. I found out that it is possible to separate the ratchet wheel from the mainspring-barrel/barrel-arbor and to reassemble it with the help of a riveting machine for a more thouroughly cleaning.
    I think that this can be a weak spot, because of the tremendous power of the mainspring focused on this tiny join.
    But the use of a traditional screw would have meant a thicker movement.

  2. such an amazing article the images of watches is so wonderful an your article is informative full knowledge about Zenith the watch feature is amazing and dial looking good i like this watch

  3. Thanks Christian, The watch is sitting on my arm and runs like a dream.
    Did not realise the complex mechanism on this watch.

  4. Have you considered taking the rotor off before removing the movement from the case? I find it more convenient when ever possible.

  5. How do you compare this dial with similar level vintage dials? It seem there is already some damage at 1 o’clock (near the 30h mark of the power reserve indicator). And the (probably) CNC finishing is not looking quite sharp in the macro shoots. This is not a cheap watch so I’m a bit surprised. Maybe i’s just an illustion.

  6. Amazing work as always. Is 8217 your braking grease of choice? Also, if grease is NOT applied to the barrel wall, can that lead to knocking/banking?

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