Clean GMT Master II Crystal Gasket rework

[germanynrw]

Guys one stupid question, which one is the crystal ring? It cost as gen most like 250-400€ .

 

[kino0924]

Guys one stupid question, which one is the crystal ring? It cost as gen most like 250-400€ .

What crystal ring are you referring to???

 

[TokyoBlonde]

There is one solution in the post immediately above yours. Personally I keep an assortment of gaskets on hand and pick the one that produces the best level of date magnification as the first priority with crystal sitting height as a close second goal.

Which crystal gasket should I use?

Crystal gasket shave - DIY

I'm in the same situation. I have a Pepsi CF GMT V3 and got myself a gen crystal. I took it to a watch maker who told me it won't fit. I didn't ask him if he tried the CF gasket or the gen one (not sure the gasket was in the package, but I think so).

If I understand your other post correctly, I should find a 3.1 mm or a 2.85mm gasket for the gen crystal?

 

[xZeroCoolx]

I'm in the same situation. I have a Pepsi CF GMT V3 and got myself a gen crystal. I took it to a watch maker who told me it won't fit. I didn't ask him if he tried the CF gasket or the gen one (not sure the gasket was in the package, but I think so).

If I understand your other post correctly, I should find a 3.1 mm or a 2.85mm gasket for the gen crystal?

I have had the best luck using a 2.7mm gasket with the gen crystal. Seems to have the most accurate date magnification to me.

 

[TokyoBlonde]

I have had the best luck using a 2.7mm gasket with the gen crystal. Seems to have the most accurate date magnification to me.

What about the concern that it won't fit? And where should I look for gaskets? Ebay?

 

[xZeroCoolx]

Esslinger or Cousins UK, buy 1 from each if you are concerned about fitment.

 

[Platomates]

I'm planning to use a sub 40mm VSF crystal. Please advice gasket brand and height to achieve 2.5x magnification.

 

[Cubatobaco]

I have a gen crystal, bezel, click spring, hytrel ring, and insert on the way. Just bought a 2.7mm gasket in hopes that it will complete the install. Can't wait!

 

[ucsfl05]

I was able to swap the crystal on my VSF sub to a deep xtal. The only problem is that once I press down the metal retaining ring, the crystal is not tight (it can spin clockwise or counterclockwise freely). The ring is pressed all the way down to the flange of the case. What am I doing wrong here?

Thanks so so much for any assistance

 

[Cubatobaco]

I was able to swap the crystal on my VSF sub to a deep xtal. The only problem is that once I press down the metal retaining ring, the crystal is not tight (it can spin clockwise or counterclockwise freely). The ring is pressed all the way down to the flange of the case. What am I doing wrong here?

Thanks so so much for any assistance

Usually that’s only an issue until you install the ring around the crystal/gasket. Gasket may be too thin or compressed. I’d try a new gasket. Order a few sizes for trial and error. It’s a tedious process and can be frustrating, but you’ll get it.

 

[ucsfl05]

Thanks so much!

 

[rnrprof]

After many trials i can say that cf crystal has to go with stock cf gasket only otherwise you cant fit the crystal holder as stock cf gasket is thin and soft, way different from gen/aftermarket gaskets(thicker and harder).
Cf gasket has also a sort of curve at the edge that stays near to the case.
That curve matches exactly the shape of the stock crystal holder.
That's the reason why it's really hard to achieve the waterproof if you swap gasket.
If you try to shave the stock gasket in order to achieve gen crystal height you will end up losing the waterproof.
Furthermore you have to consider also the tension of the crystal holder as if you press it on a gen gasket you risk to compromise the bezel turning.
If you want to go in the crystal/gasket mod direction you have to be prepared to try many different combo until you find the right one as cf mid cases are not all identical too...
It's a fucking mess...

Right on. Best response ever. It's not as easy as it sounds, and I've literally done over 500 gmts CF with my crystal using tools like Rolex

 

[rnrprof]

I'm in the same situation. I have a Pepsi CF GMT V3 and got myself a gen crystal. I took it to a watch maker who told me it won't fit. I didn't ask him if he tried the CF gasket or the gen one (not sure the gasket was in the package, but I think so).

If I understand your other post correctly, I should find a 3.1 mm or a 2.85mm gasket for the gen crystal?

Watchmaker needs to be extra careful, as the new v3 clean pepsi inserts break VERY easily

 

[CTbeforeLP]

I've worked on approximately 15-20 GMT builds.

For these projects, I typically use a 2.7mm gasket (Clark is my go-to, though I’ve also used Gen). I’ve worked with both Gen and stock CF crystals.

Common Issues and Fixes:

1. Seconds Hand Sits Too High
A common problem with the 2.7mm gasket height is the seconds hand sitting too high, which may cause it to touch the crystal. To resolve this:

Press the seconds hand closer to the minute hand.

Test the assembly in several positions to ensure the seconds hand doesn’t come into contact with the minute hand at any point.

2. Tension Ring Challenges
Another issue I’ve encountered with both Clark and Gen gaskets is the difficulty in pressing the tension ring around the gasket. Here’s how I address this:

Use a Dremel to polish the inner diameter of the tension ring for 2-3 minutes. This gives it a smooth surface and can slightly reduce the inner diameter if needed.

Apply silicone grease to the inner surface of the tension ring to ease the process of pressing it around the crystal gasket.


I’ve had no issues achieving and maintaining water resistance

 

[kino0924]

To resolve this:

Press the seconds hand closer to the minute hand.

When you say press second hands closer to minute hands,
Did you just press again with hand tool?
Or did you make second hand shorter like other post described?
I've been shaving second hand to make it sit shorter and its quite tedious task.

 

[CTbeforeLP]

When you say press second hands closer to minute hands,
Did you just press again with hand tool?
Or did you make second hand shorter like other post described?
I've been shaving second hand to make it sit shorter and its quite tedious task.

Yeah I use the hand pressing tool to push it further down. Just have to be very careful. You can also do it your way too, but I feel like it's not something I would like to take on. Lol

 

[kino0924]

Yeah I use the hand pressing tool to push it further down. Just have to be very careful. You can also do it your way too, but I feel like it's not something I would like to take on. Lol

To be honest, its very tedious tasks to shorten second hand.
I will try your method on next GMT that I have and post result.

Thanks again!

 

[Cubatobaco]

To be honest, its very tedious tasks to shorten second hand.

Yes! See @KJ2020 project with his DJ41.

 

[KJ2020]

To be honest, its very tedious tasks to shorten second hand.
I will try your method on next GMT that I have and post result.

Thanks again!

It's not that bad bro. Just takes some patience and care.

Here's a recent quote from another member

I was planning on trimming the centre wheel but did the hands instead. Seems daunting but actually quite simple. 600 grit sand paper does the job perfect.

I used a staking block to lie the hand on.

Bracelet tape underneath the hand and then rodico on both ends of the hand to keep it in place.

Then, using the 600 grit sand block, gentle push in one direction swapping over after every 20 brushes. Takes a while to get it sanded down a whole 0.5mm but result works fantastic.

Finally, I also had to tighten the collet of the seconds hand to make sure the hand stays pressed in deeply just over the minutes hand. Otherwise, over time, the seconds hand would have loosened back up a little. Every 0.1mm counts with this one.