The Rolex GMT was designed as a watch suitable for the
aviation industry What makes this watch unique is that it has a fourth hand
which facilitates the display of an additional time when used in conjunction with the
markings on the outer bezel I was recently contacted by friend who mentioned they would
like their watch serviced as it had not been looked at in quite some time We agreed to meet and he presented me with this lovely 18
carat gold Rolex GMT Master ii This watch looked in great condition and he had obviously
looked after it very well He has owned it for only 18 months after buying it used and
it is not clear wether the movement had been serviced regularly by a Rolex
authorised service centre or not but as we shall see soon I would suggest it wasn’t due to some marks and evidence of
over-oiling Now I know it wouldn’t surprise you if I state that this is
not a cheap watch in fact, I have seen them being sold online for substantial
amounts of money and they tend to hold their value very well But wether you’re a fan of Rolex or not it has to be said
that the movement quality in these watches are most certainly on the high end I’m sure that seems like I’m stating the obvious but it
doesn’t always hold true that you get what you pay for when purchasing luxury products In this case, with these watches I would most certainly
state that you do get a lot of watch for your money The movements are developed by Rolex and they are well
designed. I mean, as we shall see soon this watch movement has not had the best quality of
servicing in the past and in particular the lubrication is certainly not to Rolex
standards but the real world performance is still holding up. I am
getting readings of around +5 or 6 seconds a day despite the above Now I am not an authorised Rolex service technician myself,
neither have I been trained by Rolex I have been a professional independent watch repairer for
several decades but I never wanted to specialise in a particular brand so the methods shown in this video may not be official
methods as taught by Rolex but they do stack up with general watch repairing principles The owner is fully aware of this and has accepted that fact So in this video I am going to strip down the movement, well
as you can see I have already started the parts will be cleaned off camera and then I shall
rebuild the movement lubricating it as I go along And finally I will see about tightening up the performance Although it is running well at the moment I suspect we can get a better result once the movement is
cleaned and lubricated But as you can see, I have removed the movement from the
watch case and I have taken off the dial and hands and of course the calendar ring and what we are looking at now is the
additional GMT complication To expose the GMT works I shall need to remove two screws
holding down the cover plate here And now I can remove the GMT components The date indicator seating is held secure with four blued
screws With regret, these screws have been slightly damaged in the
past and unfortunately that will be a common theme as I continue
to dismantle this movement Removing the date indicator seating exposes the calendar and
keyless works Looking at the under side of the date seating, I can see a substantial spread of oil most likely spread
from the keyless works But I shall continue and remove the date wheel Now it should be noted that there is a small jewel resting
on the Yoke and is held under tension against this wheel’s cam So here we can see more evidence of too much lubrication these intermediate wheels are flooded So now I can remove the balance assembly The balance bridge is held secure with two screws And now I can remove the automatic mechanism which comes off as a complete module I will dismantle the auto mechanism shortly but for now I
will let down any residual power from the mainspring and dismantle the
ratchet wheel And look at the oil down the screw hole of the barrel arbor Oil has absolutely no business being there at all so that is
really quite bizarre And now I can remove the train wheel bridge, and again, we
are seeing scuffs and scratches on these screw heads which is a bit of a shame So that’s the train and escapement removed I can now remove the barrel bridge assembly and remove the
mainspring barrel And here we can see again evidence of over-oiling The click spring doesn’t want to be separated from the click Sadly we can see some scratches here on the mainspring
barrel And this is the balance hack which arrests the balance when the crown is pulled out to the hand set position Now I can remove the keyless works and I do apologise for my video framing here, I didn’t
realise until too late that I had gone off camera Luckily I had this picture in picture shot from the live
stream of this service so this shot is not completely un-interesting I have opened the barrel lid here and as you can see there is quite a lot of gunk inside - dried up grease I will remove the mainspring before cleaning but for now I
will dismantle the automatic module And that’s it - the movement is fully stripped down and
ready for the cleaning machine I have cleaned most of the parts in the machine and will
clean some manually I will also need to treat some parts with a product called
Fixodrop which will help prevent the new fresh oil from leaving it’s
position And with the parts cleaned and treated I can start the
rebuild and I shall start by assembling the barrel and mainspring To replace the mainspring into the barrel I will be using my
set of mainspring winders And here I’m choosing an appropriately sized attachment so that the spring can be installed without damage Now this being an automatic watch the barrel walls need an application of a special breaking
grease and you may notice some graffiti inside the barrel looks like the number 19 And after winding the mainspring into the tool I can
transfer it into the barrel And with that done, I can replace the barrel arbor and the
barrel lid And now I am assembling the winding bridge with the crown
wheel and it’s core And with that done, I will now assemble the automatic module And now I will assemble the keyless works I can replace the balance hack and the winding bridge Now I will install the minute pinion and it’s bridge And in goes the mainspring barrel and it’s bridge Now I’m installing the intermediate crown wheel and its core
and with the sliding gear And in goes the click and click spring Now I neglected to treat the escape wheel and pallet fork
with Fixodrop earlier so I can get that out of the way now And with that done, I can assemble the train of wheels along
with the train wheel bridge And on goes the ratchet wheel I can now install the pallet fork - off camera I lubricate the pallet stones and escape wheel teeth With that done, I can install the balance assembly and here you can see the screw used on the right looks quite
scuffed, impossible to see with the naked eye as it really is that small, but shot with a 4K camera and a
macro lens it doesn’t look so good I’m pretty sure if this was sent to Rolex they would simply
replace the damaged screws and charge accordingly, polishing these screw heads would be
another option but that is a very time consuming task which doesn’t fall
into the category of maintenance servicing but rather restoration work Now I can secure the automatic module to the movement Turning my attention to the dial side, I can now re-assemble
the calendar and motion works And finally, I can assemble the GMT complication So now I’m ready to replace the dial and hands and refit the
movement to the watch case And on goes the oscillating weight It is not common for Rolex calibers to have a simple
regulating arm for adjusting the rate but rather adjustments are made to weights on the balance With this movement the weights are actually screwed to the
inside of the balance rim and they have a special shape meaning they can only be
adjusted with the use of a special tool called a Micro Stella tool This tool has a socket to interface with the adjustments
perfectly and attempting to turn them without this tool will likely
end badly The balance will usually have two screws opposite each other although this movement has four and the two opposites should
be adjusted evenly If they are adjusted towards the balance rim, the rate will
be reduced and if they are adjusted towards the balance staff the rate will increase The tool has markings and a weight which shifts position as
you adjust the angle whilst turning the screw Each marking represents 1 second per day of adjustment So with this watch I am currently seeing an average rate of
+5 or 6 seconds per day to tighten this up I will use this tool to adjust the
weights towards the balance rim This may disappoint you but I have no intention of doing
this on camera as I need get in real close and not risk damage to parts I
know will be extremely hard for me to replace but I will post a document with the full instructions as a
PDF for you to download from the Files section of our watch repair Facebook group or from
my website there will be a link in the description of this video So here is a before And now that I have adjusted the rate, here is a 5 position
readout So that’s it, I know this is not serviced to Rolex standards
but the owner is aware of this Of course, my recommendation to him would be to have this
watch overhauled by Rolex officially in particular to replace the damaged screws and the
mainspring and barrel I am pretty sure that graffiti in the barrel is not from the
factory But these problems are cosmetic and will not really affect
the running of the watch That being said, the performance is really looking good I would like to thank the owner for allowing me to use this
watch on the Watch Repair Channel But what did you think about this watch? Please let us know your thoughts in the comments section
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you in the next one
