WS 20: Replacing the battery on a Patek Philippe Ladies' Quartz Nautilus
with a "split stem" or "two piece crown stem"

Foreward: "front loaders"

There are many types of so called "front loaders", watches with movements that are removed from the front after having removed the crystal and or bezel. There are also different types of split-stems. Therefore please note that you cannot simply transfer these instructions to your watch. The best way to start is with a service manual. There you will find all the information to safely remove the movement. If your watch is vintage (e.g. a Timex) and you cannot get your hands on a manual, ask on MOD CENTRAL for advice.

Single piece case

The case back shows no groves or notches, it clearly is a single piece case.

The split-stem

For this particular watch and split-stem, the removal of the crown part is really easy. You can simply pull the crown past the date setting (normally called position 2) and the split-stem will disengage. Please note that I not removed the top part (bezel) yet. I found it is safer to pull out the crown part of the stem with the watch still closed and the movement safely held in place.

Removal of the top part (bezel and crystal)

This Patek Philippe "Nautilus" features a simple and smart construction. The top part of the watch case (bezel with crystal) is held by four screws. After having removed these screws, the top part can be lifted off.


 

Removal of the movement

Place a movement pad carefully onto the open watch front and then turn both over. The movement lays now dial down on the pad and the battery can be easily exchanged. In this case a R364 or SR621SW.



The crown is in its position for illustration purposes only. The wide gasket ring (bezel side) is not in the picture but might need a bit of silicon grease

Reassembly

Reinsert the movement making sure it's split-stem fits into the crown tube. Again, I prefer to insert the crown after the front has been closed. Make sure the crystal inside is clean, apply a bit of silicon grease to the gasket and close the front with the four screws.

Feeling the alignment

For this particular watch, you can insert the crown part of the stem and turn it while applying only little pressure. You will immediately feel, once the two parts of the stem are aligned. Then press the crown carefully in and the split-stem will engage with an audible click. To make sure you got it right, pull the crown again out to the setting position. If the split-stem has engaged properly, you can now set the time and date.