I finally replaced the rather incorrect Sub crown on my cheapo GMT with the proper 6mm part and therefore had a crown and tube left over that I was itchin' to put to use. I recently got another cheap Sub and it came with a "twin-lock" type seal arrangement which I wasn't real happy with so the light bulb went off. I decided to put the crown and tube I removed from the GMT into the new Sub. Before I replaced the tube on the previously mentioned GMT Master II I had never changed a tube and knew nothing about it so I just approached it from what appeared to me as the logical way to do it. This was my second swap.
Here's how I did it:
The first couple of pictures removing the case back and stem didn't turn out (some sort of image ghosting) for some reason so you'll have to use your imagination as I'm too lazy to tear everything part and re-shoot them! But, I basically remove one of the link screws and separate the band - I think this is easier than removing a spring-bar but some might prefer to do it that way. This allows unhindered access to the case back which can be removed with the opener of your choice, I use a "sticky-ball". Once the back is removed pull the stem out to the "time set position", depress the "latch", and remove the stem by gently pulling it out of the case. This picture shows the a21j stem retainer release from the reinstall picture because for some reason the removal picture didn't turn out:
Then the stem can then be removed. You will notice that there is no external O-ring on the old tube and that's the reason I am changing it:
As with most of the lower priced reps this one has the movement secured by a plastic retainer/spacer (white in this case) which you simply pull up and off:
At this point I usually put a surgical glove (non-powdered) on my left hand, and turn the watch over and let the movement assembly drop into my hand. I have been reminded by experts that at this point the movement assembly should be stored in a covered tray, or at least protected in some manner (between layers of watch paper). I'm sorta lazy and and haven't developed all of the good habits I should so I just set the movement aside on a paper towel - which is another no-no:
Although I think there is a special wrench to remove genuine Rolex tubes this rep tube didn't look like there were any provisions for any kind of wrench. I snagged a small tapered reamer out of my toolbox (nice to be a machinist sometimes) which I then lightly tapped into the tube. I have read that some use a small E-Z Out and see no reason why that wouldn't work just as good. Since writing this I have started using the smallest EZ-Out or a three-square jewelers file to remove the tube:
The tube has a standard right-hand thread so it unscrews with a CCW rotation:
After a few turns the tube is removed:
Here you can see the physical difference between the new and old tubes:
I lightly pressed the "new" tube onto the tapered reamer and applied just a bit of blue thread locker (Loc-Tite, Permatex, etc.). I now usually use a tube wrench or the three-square file to install the new tube. I really should have removed the internal O-ring before doing this, and I thought about that afterwards, but it was too late and I appear to have gotten lucky - this time:
I got lucky this time in that the replacement tube screwed right in. Often, especially when installing a gen tube, the existing hole will need to be re-tapped and sometimes drilled larger and taped. Now my normal procedure is to re-tap, or "chase", the existing threads just to ensure the tube seats properly and also minimizing the possibility of breaking off a tube. Install the tube into the case by engaging the threads and rotating it in a CW direction until just snug. You don't want to risk breaking off the tube, stripping it's threads, or "reaming out" the inside of the tube. The thread locker will keep it plenty secure once it cures:
After the tube is installed clean up the excess thread locker and if you properly removed the internal O-ring then lube it up with silicone grease and reinstall it:
Put the movement assembly back into the case and reinstall the stem. This is the perfect time to apply a bit of silicone grease to the O-ring up in the crown, and the external O-ring to help ensure some sort of water resistance. Reinstalling the crown/stem assembly is basically the opposite of removal - insert the stem through the tube and into it's hole in the movement, then depress the stem release and press the stem inward turning slightly if needed:
You will feel it sort of click into place and you can then release the latch. Make sure you can wind, set date, and hack and set time. I got lucky on this one as the stem and crown assembly I removed from the other watch just happened to be the correct length so I didn't have to "modify" the stem length. If all is good then screw down the crown:
Reinstall the movement retainer (or screws and tabs if yours is a higher quality rep):
If you are satisfied that the dial is aligned and everything looks good grease the case-back O-ring and reinstall and tighten the case back:
Put the band back together by lining up the link and reinserting the screw:
Using the proper screwdriver lightly rotate the screw CCW until you just feel a light "click" reverse rotation direction and snug up screw. Not too tight as you don't want to strip the threads
:
This would be a perfect time to double-check all of your band screws to make sure they are snug. Hey, you're done!
Here's how I did it:
The first couple of pictures removing the case back and stem didn't turn out (some sort of image ghosting) for some reason so you'll have to use your imagination as I'm too lazy to tear everything part and re-shoot them! But, I basically remove one of the link screws and separate the band - I think this is easier than removing a spring-bar but some might prefer to do it that way. This allows unhindered access to the case back which can be removed with the opener of your choice, I use a "sticky-ball". Once the back is removed pull the stem out to the "time set position", depress the "latch", and remove the stem by gently pulling it out of the case. This picture shows the a21j stem retainer release from the reinstall picture because for some reason the removal picture didn't turn out:
Then the stem can then be removed. You will notice that there is no external O-ring on the old tube and that's the reason I am changing it:
As with most of the lower priced reps this one has the movement secured by a plastic retainer/spacer (white in this case) which you simply pull up and off:
At this point I usually put a surgical glove (non-powdered) on my left hand, and turn the watch over and let the movement assembly drop into my hand. I have been reminded by experts that at this point the movement assembly should be stored in a covered tray, or at least protected in some manner (between layers of watch paper). I'm sorta lazy and and haven't developed all of the good habits I should so I just set the movement aside on a paper towel - which is another no-no:
Although I think there is a special wrench to remove genuine Rolex tubes this rep tube didn't look like there were any provisions for any kind of wrench. I snagged a small tapered reamer out of my toolbox (nice to be a machinist sometimes) which I then lightly tapped into the tube. I have read that some use a small E-Z Out and see no reason why that wouldn't work just as good. Since writing this I have started using the smallest EZ-Out or a three-square jewelers file to remove the tube:
The tube has a standard right-hand thread so it unscrews with a CCW rotation:
After a few turns the tube is removed:
Here you can see the physical difference between the new and old tubes:
I lightly pressed the "new" tube onto the tapered reamer and applied just a bit of blue thread locker (Loc-Tite, Permatex, etc.). I now usually use a tube wrench or the three-square file to install the new tube. I really should have removed the internal O-ring before doing this, and I thought about that afterwards, but it was too late and I appear to have gotten lucky - this time:
I got lucky this time in that the replacement tube screwed right in. Often, especially when installing a gen tube, the existing hole will need to be re-tapped and sometimes drilled larger and taped. Now my normal procedure is to re-tap, or "chase", the existing threads just to ensure the tube seats properly and also minimizing the possibility of breaking off a tube. Install the tube into the case by engaging the threads and rotating it in a CW direction until just snug. You don't want to risk breaking off the tube, stripping it's threads, or "reaming out" the inside of the tube. The thread locker will keep it plenty secure once it cures:
After the tube is installed clean up the excess thread locker and if you properly removed the internal O-ring then lube it up with silicone grease and reinstall it:
Put the movement assembly back into the case and reinstall the stem. This is the perfect time to apply a bit of silicone grease to the O-ring up in the crown, and the external O-ring to help ensure some sort of water resistance. Reinstalling the crown/stem assembly is basically the opposite of removal - insert the stem through the tube and into it's hole in the movement, then depress the stem release and press the stem inward turning slightly if needed:
You will feel it sort of click into place and you can then release the latch. Make sure you can wind, set date, and hack and set time. I got lucky on this one as the stem and crown assembly I removed from the other watch just happened to be the correct length so I didn't have to "modify" the stem length. If all is good then screw down the crown:
Reinstall the movement retainer (or screws and tabs if yours is a higher quality rep):
If you are satisfied that the dial is aligned and everything looks good grease the case-back O-ring and reinstall and tighten the case back:
Put the band back together by lining up the link and reinserting the screw:
Using the proper screwdriver lightly rotate the screw CCW until you just feel a light "click" reverse rotation direction and snug up screw. Not too tight as you don't want to strip the threads
:
This would be a perfect time to double-check all of your band screws to make sure they are snug. Hey, you're done!
