Another day, another Zenith… Parashkev from London sent this one in, and he complains that the auto winder doesn’t work, and he would like a new sapphire crystal.
The amplitude is too low, so the movement does definitely need a service.
With the customer saying that the auto winder doesn’t work, I already have an idea what to expect, and the little specs of dirt in the movement confirm my fears.
With the rotor removed, you can see the bits of abrasion all over the movement.
The bottom plate looks clean, and there shouldn’t be any problems.
The chronograph layer is taken off, and I’m curious what I will see underneath. I have an idea …
That’s some serious abrasion here.
And here is the culprit. The ratchet wheel driving wheel has a shorn off pivot, so the wheel tilted, and ground into the plate.
If this were a fluke, I wouldn’t say anything. But this is not the first Zenith I’ve had in here with the same damage, and more often than not, these Zenith movements are subject to excessive wear. Too much power, too fast beating… I now understand why Rolex took this movement down to 8 b.p.s. when using it in the Daytona.
the mainspring is still very spritely, and I don’t change it on these movements, as there is enough grinding the movement to dust going on, anyway. It doesn’t need more power!
The dirt has spread throughout the top plate.
Now it’s time to turn around, and take apart the bottom plate.
All looks well here.
Having cleaned all the parts, I start putting the movement back together. The cleaned and oiled mainspring goes back into the barrel.
Then I put the balance jewels back in.
The gear train is back, and the new ratchet wheel winding wheel is in place. All nice and clean.
The base movement is beating again.
And looking great.
Now I can put the chronograph layer back on.
The chronograph bridge goes on, and I can adjust the depthing.
That done, I put the bottom plate back together.
The dial and hands go on.
And finally the rotor and a new case back gasket.
A last adjustment.And all is well again.