As I was flipping through a price guide published for watch collectors I halted on a picture of a timepiece with a very interesting complication. The watch in question was produced by Favre Leuba in the early 1960’s and in addition to the standard mechanical movement it also housed an aneroid barometer for the purpose of determining altitude. The watch is known as the Bivouac and is quite rare and prized by collectors.
In reading further I discovered Favre Leuba is a revered watch manufacturer whose history stretches back to the eighteenth century. In the late 1950’s and early 1960’s they began producing some cutting edge tool watches such as the Bivouac and a diver’s watch known as the Bathy which incorporated a working depth gauge. Their chronographs of the era used the highest quality movements produced by Valjoux.
The watch in this post is not a Bivouac, but instead a three register chronograph from Favre Leuba. There may not be a minute aneroid barometer inside but I was still excited to engage in the service as this watch houses a proper Valjoux 71 chronograph movement.
The watch came from an antique dealer who originally purchased it in an estate sale. It appeared to have passed hands just once but was certainly lacking a recent service The crystal was worn, the case scuffed, and the minute register hand had a life of it’s own.
A few quick turns of the crown brought the movement to life. The beat was loud and constant but removal of the caseback revealed some problems; the Minute Recording Jumper did not make contact with the Minute Recording Runner and the Chronograph Runner had clear and ominous scratches.
Examining the Chronograph Runner under the microscope confirmed that the Hammer was sliding across the wheel when the chronograph was reset. I assumed this was the result of either a bent runner or hammer.
With the movement in a clear need of service, I proceeded to break it down for cleaning.
As usual, I removed the hands under the microscope to ensure the little chance of damaging the dial. I judged from the architecture of the hands and the radium on the dial that this watch probably dates to the late 1950’s.
With the dial off and set aside for safekeeping, I got my first good look at the new (to me) chronograph movement.
Most chronograph movements from the period 1930 – 1970 utilized the same basic principle for starting and stopping the sweep second hand and recording elapsed minutes. Where the designs diverge is in the engineering of the hour recording mechanism. Lemania and Venus both utilized a friction clutch which is connected directly to the mainspring barrel. The Valjoux design uses a Driving Pinion and laterally engaged clutch (Conveyer) to drive the Hour Recording Runner. I like the Valjoux design best although there are quire a few parts to keep track of.
Working my way step-by-step through the Esembl-O-Graf, I broke down the hour recording mechanism before moving on to the top plate.
Despite having previous of experience with similar chronograph movements, I took many pictures during disassembly both to aid reassembly and also to help understand the root causes of the issues identified earlier.
Under the microscope problems that might have been missed are brought to light. Here, a close examination of the Minute Recording Runner revealed an interesting wear pattern.
As the gears, levers, and springs of the chronograph came away I could examine the pivots and jewels for damage or wear.
After painstakingly removing the chronograph works, the top plate came away to reveal a very straightforward gear train.
The underside of the top plate hides the winding mechanism (Crown Wheel, Click, and Click Spring).
It’s hard not to notice how robust this movement is as you break it down. The origin of the Valjoux 71 dates to around 1914 and may have originally been intended for use in pocket watches; the size of the movement, 31mm across, requires a rather large watch case to house it and wrist watches of such size were not very popular until the late 1960’s. When you wind the mainspring a deliciously crunchy noise is emitted and you can feel the engagement of the Crown and Ratchet Wheel gears through your fingertips.. The movement, housed in a stainless steel case, is heavy and the weight in your hand inspires confidence.
I cleared the jewels with pegwood and ran the movement through the L & R machine for about twenty minutes. It returned to the workbench sparkling clean and ready for assembly.
Although the Balance can be run through the L & R machine, I usually elect to clean it by hand just to make absolutely certain the hairspring doesn’t tangle and the pivots are taken care of. Here I’ve separated the Balance to treat it with a bit of One-Dip.
Favre Leuba opted for a Breguet overcoil to the hairspring which improves the timekeeping, but will also make it a little more challenging to correct any beat error.
Reassembly of the base movement proceeded without incident until it was time for testing. The movement registered a very poor amplitude; a bit of investigation confirmed the source to be a worn out Center Wheel bushing.
Too much play in the bushing resulted in the Center Wheel and Chronograph Runner tilting between the top and bottom plates. This in turn caused the Hammer to slash across the Chronograph Runner when the chronograph was reset.
Naturally I was happy I had solved the mystery of the scratched Chronograph Runner. Sadly it also meant the plate needed to be rebushed or jeweled. I opted for the latter.
I measured the diameter of the Center Wheel pivot to determine the inside diameter (1.10mm) then selected the jewel with the smallest outside diameter available from the supplier (2.6mm). Next I needed to ream the plate to accept the jewel. Using the Seitz jeweling tool and reamers of increasing size the hole was gradually increased to 2.59mm.
Following a bit of cleanup with a deburring tool, the jewel was pressed in using the same Seitz tool. The meticulous preparation paid off and the jewel fit snugly in the hole.
The chronograph works were assembled in reverse order again using the Esembl-O-Graph guide.
The Minute Recording Jumper, which formerly did not make contact with the Minute Recording Runner, was carefully coaxed back into shape. The jumper is extremely delicate and very difficult to replace, so extreme care was exercised.
I noticed a screw seemed to be missing from the bottom plate which placed additional tension on the Hour Flyback Spring. Luckily, a bit of digging in my parts bin produced a suitable replacement.
With the movement fully assembled, final testing could begin. Chronograph adjustments are always a bit tedious but you just have to stick with it. Often you’ll think the job done only to discover a hiccup once the hands are back on. The most important thing is to have a properly functioning base movement though.
I cleaned the case and pushers and fitted a new crystal and stem tube before reinstalling the movement. I’ll still have to order a new strap but I haven’t decided just yet what will look best.
I’ll let the watch run for a week to distribute the oils and allow any gremlins to surface before calling the job done. I’ve already noticed the minute recording hand is one tick off of zero when it’s reset- thankfully that’s a quick and easy fix.
Just for a size comparison, I snapped a picture of the Favre Leuba next to the Accutron I serviced earlier. You can see what a beast this chronograph is!
I have now serviced a Landeron, Pierce, Lemania, Venus, and Valjoux chronograph movement. That’s a lot to tick off the bucket list! Next up is a Martel (Universal Geneve) and hopefully not too long after that an Excelsior Park movement.