Service: Pontiac Dress Watch with ETA 2390 Movement

This is one of my dad’s watches. A nice Pontiac dress watch with an unusual case because the bottom part is stainless steel while the top part is gold plated.

It has an ETA 2390 movement. An older version because it still has a fixed stud holder. That dates the watch to the mid to late 50s.

The watch did run but it was time for an overhaul. As a watch geek, I can’t have my father running around with a watch that’s overdue for a service.

Disassembly

Remove all power from the mainspring. This is to prevent any damage while working on the wheel train.

Move the click away from the ratchet wheel while letting the crown slip between your thumb and index finger.

Lift the balance and the pallets.

Remove the ratchet wheel and the crown wheel.

The ETA 2390 doesn’t have a traditional click with a click screw but it has a little shaped bar with the click spring next to it. It’s a very simple but effective design.

You don’t have to worry about the cannon pinion. This movement uses a driving wheel instead of a center wheel and it’s one part with the cannon pinion.

Remove the barrel bridge.

Lift the wheel-train bridge to gain access to the wheel train.

Lift the sweep second wheel, the third wheel, and the escape wheel.

Remove the barrel and the intermediate wheel.

Flip the movement around and start with the bottom plate.

The ETA 2390 has a separate minute work cock that covers the minute wheel and the setting wheel. Remove this first so you can lift the driving wheel with the cannon pinion. Then, lift the setting lever spring and remove the keyless works.

Finally, don’t forget to remove the lower cap jewel with the endpiece for the escape wheel.

Pre-clean the pivot holes and bearing jewels with peg wood.

Clean all the parts in the watch cleaning machine.

Assembly

Start with the lower cap jewel with the endpiece for the escape wheel. It would be best to also install the set lever screw at this point.

Place the intermediate wheel and the barrel in position.

Place the escape wheel, the third wheel, and the sweep second wheel in position and reinstall the wheel-train bridge.

I forgot the set lever screw so I installed it at this point. It’s not a big problem but it’s easier to do with an empty base plate.

Install the barrel bridge, the click, and the click spring.

Place the crown wheel ring, the crown wheel, and the ratchet wheel in position.

Turn the movement around and start with the keyless works.

Install the winding pinion, the clutch, the winding stem, the yoke with the spring, and the setting lever spring.

Place the driving wheel with the cannon pinion, the setting wheel, and the minute wheel in position and install the minute work cock.

Flip the movement to the top plate and reinstall the pallets and the balance.

Install the hour wheel which has a built-in dial washer. Attach the dial and case the movement.

Fit the hands and use the hand blower to clean the dial before you install the crystal.

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What do you think of this Pontiac dress watch? Do you have a similar one or would you like to add one to your collection? Let me know in the comments below.