Precision from Saxony: Servicing the Mühle Glashütte Terrasport II
At W.E. Clark & Son, we see a diverse array of timepieces, but there is always something particularly satisfying about working on a watch from the German watchmaking hub of Glashütte. The Mühle Glashütte Terrasport II is a quintessential “Flieger” or pilot’s watch—functional, legible, and robust.
However, even the most rugged tool watches require expert intervention when the mechanical components reach their limit. We recently had a Terrasport II on the bench that perfectly illustrates a common challenge with modern automatic movements.
The Heart of the Matter – The Sellita SW200-1
The Terrasport II is powered by the Sellita SW200-1. While this movement is a “workhorse” of the industry, Mühle doesn’t just drop it in “off the shelf.” They add their own bespoke touches, including their patented “woodpecker neck” regulation and a beautifully decorated rotor.
Despite these high-end refinements, the fundamental mechanics remain susceptible to wear and tear over years of daily use.
The client brought this piece in noting that the watch was no longer winding correctly and felt “crunchy” when turning the crown. Upon disassembly, the culprit was immediately clear: the ratchet wheel had several broken teeth.
This is a known vulnerability in the SW200-1. The teeth on the ratchet wheel are under significant tension; if lubrication has dried out or if the user is particularly vigorous with manual winding, the metal can eventually fail. When these teeth break, the shards can migrate through the movement, risking further damage to the gear train.
Mühle Watch Repair: The Repair Process
To restore this Terrasport II to factory standards, our BHI-accredited watchmaker performed a full movement overhaul, which included replacing three critical components:
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The Ratchet Wheel: Replaced with a brand-new, genuine part to ensure smooth winding.
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The Ratchet Driving Wheel: As these two wheels interact directly, we replaced the driving wheel to ensure the gearing interface was perfect.
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The Barrel Complete: To guarantee a full power reserve and consistent torque, a fresh barrel (containing the mainspring) was installed.
During a full service the movement is fully disassembled and cleaned in our specialist watch movement cleaning machine. It is then reassembled, and lubricated with specific Moebius oils, before being timed and adjusted.
Results and Testing
After the service, the Terrasport II was subjected to a multi-position timing test and a pressure test. The result is a watch that winds as smoothly as the day it left Saxony, ready for many more years on the wrist.
Watchmaker’s Tip: If you feel increased resistance or a “skipping” sensation while winding your automatic watch, stop immediately. Continuing to wind a watch with a failing ratchet wheel can spread metal debris throughout the movement, leading to a much costlier repair.
At W.E. Watch Repairs, we specialise in servicing both modern and vintage timepieces. If your Mühle Glashütte or Sellita-based timepiece needs repairs, movement servicing, or precision tuning, our skilled watchmakers are here to help.
Take advantage of our Royal Mail Special Delivery FREEPOST service—your watch is fully insured for up to £20,000 throughout its journey, ensuring peace of mind from the moment it leaves your hands until it is safely returned.