WS 19: Servicing a SEIKO Chronograph 6138

Replacing springs correctly is in my opinion always the most complicated part of an assembly. Because one really has to know the positions of the springs. Otherwise a rather long and time consuming trial and error process could start. I have marked the corners of two big springs in the picture below with fine red lines to give you an idea what you will have to remember when reassembling.

I am not going into any details regarding adjusting this caliber during assembly. Because I can not explain it properly. Think of it as an iterative process that you check the play of all components together while eventually tweaking the tension of the springs. This procedure will need to be repeated throughout the following assembly process. Rob also told me, that he had seen quite a few 6138 that had been serviced but not adjusted. A good adjustment guarantees and error free operation for the cycle until the next service is due. Reduces wear and one effect that we can easily feel, is that the pusher action is defined, but not to soft and not to stiff.

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