clock & barometer repairs
01277 658800   Billericay


Atmos bellows refill & repair

The Atmos range of clocks by Jaeger LeCoultre (Image 1) represent the highest standard of horological engineering; so much so that service intervals can be as long as 25 years. Because these clocks run so slowly, very few parts require lubrication and so pivot holes do not clog up as quickly; hence, servicing is often restricted to a routine strip and clean of the movement and mainspring.

If mishandled, the delicate suspension from which the balance wheel pendulum hangs may break; such is the importance of locking the pendulum balance before moving the clock. Otherwise, the only parts replaced are normally cosmetic (glass, for example).

One part that can fail after many years, however, is the bellows, which sit in the large brass container on the back of the clock, known collectively as the "motor" (Image 2). Made from thin folded stainless steel and brass, the bellows contain a gas, the properties of which include a low boiling point causing the bellows to expand and contract with variations in the the ambient temperature (and pressure). This small lateral movement continually winds the mainspring.

The mainspring is not as robust as the ones in other clocks of a similar size but it is long and when fully wound it's enough to keep the clock running for up to a year (Image 3). Failure of the bellows, therefore, will not result in instant failure of the clock; it can take many months, up to a year, between the failure of the bellows and the eventual failure of the clock itself; it will begin to lose time before finally stopping.

Bellows collapse because the gas escapes. Sometimes leaks develop in the solder joint between the brass and stainless steel parts and these are usually repairable by traditional soldering techniques. Sometimes the bellows become holed and a solder repair there also works unless it's on the actual fold. However, I've also found that tiny multiple stress fractures can form in the stainless steel, especially on the folds and these are presumably caused by metal fatigue, after many years of daily expansion and contraction. This sort of damage is impossible to repair using traditional soldering techniques but I am presently working on a previously untried solution. Other bellows just seem to collapse slowly over the course of 30 years or more for reasons I've not yet discovered - there is no discernible leakage anywhere. So long as they remain sealed or can be resealed, they can refilled and made to work again.

New bellows probably cost more than £500 depending on the model. I say 'probably' because you'd be hard-pressed to get one at any price, as Jaeger and their Agents won't sell them to you. Some may not even be available at all for the older calibres. Used bellows from scrapped clocks come up from time to time but if you're thinking of buying one, you MUST first check that it has not already part-collapsed (Image 4) and that it is the correct one for your clock's calibre. Expect to pay a hefty price though; one American Atmos repairer recently offered me a repaired one for USD450 trade, "to help me out". Once you factor in Import Duty and VAT, that's almost £500! It came with no guarantee whatsoever so I declined for this reason. Image 5 shows a solder-repair to the steel part of another bellows; it's not pretty (and it's NOT one of mine) - it failed after a refill as it could not take the pressure. So a money back guarantee when you're spending that much is essential.

Now, there are only a handful of repairers worlwide and none operate with Jaeger approval; most will only supply one if you have the clock serviced by them at the same time. I only know of one specialist offering a refill service and he's also in the US. He charges $100 plus $26 return postage so with shipping out to the States it all adds up to about £120 and that's just a refill - any repair work is extra. But because of the distance and interference from Customs at both ends, it can be slow. And it's difficult to post it 'Signed For' because he uses a PO Box address. The one time I tried him myself, the parcel came back after three weeks, undelivered, so it's not the perfect solution. I don't know of anyone in the UK currently offering a similar service but after trialling and testing with another UK horologist, we are now able to refill most bellows for £125 including return postage within the UK. There are no postal delays, no Customs interference or international transit risks of loss or damage, and a turnround of three to four weeks is quite possible (subject to workloads and holidays).

This does not include any repairs so first your bellows need to pass a 48 hour pressurised leakage test. If a leak is revealed, and I think it might be repairable, I will tell you the additional cost before proceeding. At the moment a repair will be carried out only if the existing solder joint fails as trying to fill fractures in the stainless steel with solder is unreliable. Our new treatment process is still under trial so until we perfect it, we cannot guarantee to be able to repair every bellows. So if there is a leak that cannot be fixed, the empty bellows will be returned for just the postage cost plus £10 for testing.

Please bear in mind that we do not have the resources of Jaeger LeCoultre - this is, after all, just an extended hobby. But if you check my feedback on Google+ and elsewhere you will see that all my reviews are five-star, nothing less. So you can be reassured that I will do my best to provide a reliable and cost-effective service.

As always, please do NOT post or bring anything to me without contacting me first.



  • A fairly common Jaeger LeCoultre Atmos 'Living On Air' clock 528 calibre with square dial powered by gas-filled bellows on the back
  • The Atmos 'Motor' from a 528 calibre, comprising container, cover heavy spring and bellows to keep the mainspring wound
  • The mainspring barrel from an Atmos 528 calibre, dismantled to show the mainspring
  • Two Atmos bellows at room temperature, the one on the left having completely collapsed.
  • Another repairer's solder repair found on an Atmos bellows, ugly but nonetheless effective, having lasted for years