My Best Project Yet- Breitling Colt Chronographe A53035- ETA 251.262

I took chance on this Breitling during my week off at Easter, the description stated that the watch was in working order but required a new battery, had a screw missing from the bezel and had the case back seal missing. The pictures were tiny and the final line of the description stated ‘ideal for spares or repair’.

Seller’s Picture…

After patiently waiting for a few days, the package I had been waiting for finally turned up. On opening the package, the first thing that I noticed was that the crystal was heavily scratched but the watch was definitely genuine. The lume in the hour and minute hands had discoloured but the other hands and dial were in pretty good condition. The case only required a light polish and the bezel was almost as good as new. The case back as shown in the pictures displayed some marks from a past attempt to remove it. Not exactly as described but for the price I paid it didn’t matter.

Anyway, it was time to see if a new battery would get it working or whether it required some attention. Off came the case back and in went a new battery, initially it seemed as though it was working perfectly but then all the hands started spinning in different directions… It wasn’t working perfectly after all then. After consulting with one of the tutors, it was decided that a full service would get it functioning perfectly once again. The only slight problem was that it housed one of the more complex quartz movements out there, the ETA 251.262. It has 5 coils and rotors plus a large number of train wheels, the second year students had only just started working on this movement so you could say it was a bit far ahead of my current skill set. Nonetheless, I decided that I was up for the challenge and printed off the technical guide in preparation.

ETA 251.262 Quartz Chronograph Movement….

I started by uncasing the movement, removing the dial/hands, removing the bezel and removing the strap. The strap, case and bezel were put in the ultrasonic tank to be cleaned in preparation for polishing. I planned to lightly polish the case and also polish the buckle to remove all the marks. The bezel had a few marks but we don’t have the right tip of polishing wheel at school to reproduce the factory finish to a good standard so I decided to leave it as it is. The polishing would be the last part of the whole process because the movement service was the real challenge of the whole project.

The start of something…
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At this point in preparation for the work ahead, I sourced the following parts:

Full set of Genuine Breitling hands
New mineral crystal- Really wanted a Sapphire but the size wasn’t available
Full set of Genuine Breitling bezel screws
Full set of Genuine Breitling gaskets
Genuine Breitling bezel spring and click spring
Genuine Breitling crown

I was ready to get the service underway with the easiest part of the process, disassembly and inspection ready for putting it all through the cleaning machine. The number of parts in this movement compared to what I had worked on before made me slightly apprehensive but everything is logically laid out so I was looking forward to getting it back together.

Calendar work, upper magnetic screen, coils, battery and battery clamp, additional printed circuit, circuit distance piece removed…
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Upper plate including the train removed…

Electronic module, crown/stem, motion work and keyless work removed…
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The number of parts is still increasing…


Upper plate and trains ready for disassembly…


Bridge off- How many wheels?!
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Wheels removed…

Nearly there…

The extensive parts list…
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With all of the necessary parts out of the cleaner it was time to start putting everything back together. It was a daunting task but at least I had the technical guide and 3 very knowledgeable tutors to help me along the way. I didn’t take any pictures along the way because I wanted to get it all together quickly in order to keep the dust out. Instead I have put up the technical guide assembly diagrams that also show the lubrication points.

Assembly of the calendar work…

Assembly of the handsetting and electronic module…

Assembly of the electronic module and motors…

Assembly of the chronograph…

The trickiest part of the whole process was fitting the train wheel bridge, there are 7 wheel pivots to locate into jewel holes and also 3 rotors to locate into jewel holes. After several unsuccessful attempts to locate everything myself, I was helped out by one of the tutors. The size of the wheels and there close proximity to each other makes the task hard but the magnetic rotors make things even harder as they are prone to moving. Considering this is one of the more complex quartz movements and one of the trickiest to work on, I really enjoyed servicing it and I’m looking forward to working on it again at the end of the year.

With the service now completed and the battery fitted, it was time to put the movement on the Witschi Analyzer Q1 Quartz Tester. Thankfully it was running perfectly, drive level was at an acceptable level and the timekeeping was spot on. I really was pleased with myself, having managed to tackle such a complex movement at such an early stage in the course. I could now refit the dial and new hands.

Dial and hands are refitted…

Fitting the sub dial hands and the hour/minute hands was a simple process but fitting the two central chronograph hands was a bit of a nightmare. I couldn’t get the to line up with each other and hit dead centre of the dial markers. The problem arises because there is a bit of backlash in the wheels, this means the hands can move a tiny bit after being positioned and fitted. This can be quite frustrating and after 3/4 attempts, I finally got them to an acceptable standard but they aren’t perfect so I will come back to them after I have had more practice. There is just a minute amount of overlap between the two but its not noticeable unless your inspecting them really closely.

After checking all the hands were moving freely, I put the movement away so I could get the case polished and fit all the new parts. I removed the old crystal from the case and then gave the case a light polish to remove the majority of the marks. It came up really well and now looks almost new. The next job was to sand down the case back slightly to remove the worst of the deep scratches caused by someones carelessness with a jaxa tool. I then polished carefully making sure not drag any of the text, the end result is that you would never know that there were ever any marks there. The last thing to polish was the buckle from the rubber strap, it was tricky to remove the marks without dragging the ‘B’ logo but with some patience it looks like new.

The polishing was finished and after a clean in the ultrasonic tank the case was ready to accept the new parts. Firstly the mineral crystal was fitted using a Bergeon crystal press tool, a big improvement on the old heavily scratched crystal. Next I fitted the new bezel click spring and applied some fomblin grease. The bezel spring was eased into its slot on the bezel and some more fomblin applied around the bezel teeth, the bezel was then put it in position. The bezel I have fitted previously have just been friction fit and pressed on but this Breitling has a different system. There are 8 screws that apply pressure to the bezel spring to hold it on, a small amount of blue loctite is added to make sure they don’t work themselves loose.

The next job was to change the faulty crown, to do this I held the stem in a pin vice before heating up the crown and then gently twisting it off. The stem was cleaned up and a small amount of loctite added to the thread, the new crown was then screwed into place. Finally I fitted the new gaskets and the case was ready.

Ready to go into the case…

In position…

I really enjoyed this project and with the amount of work I have completed, consider it the best one I have done yet. The whole process has taught me any number of things, from fitting multiple hands to changing a crown, but servicing one of the most complex and tricky quartz chronograph movements has to be the biggest learning experience. Its also nice to have something to show at the end for all my hard work and something that I can hang on to. If you have made it this far, thanks for reading and I hope you have enjoyed the whole process as much as I have.

And finally, here are the results of my hard work…
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Settled in to its new home…

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