Seiko 4402-8000 Second Hand Stopping, Not Touching Crystal...

[JBerry]

I recently serviced this Seiko 4402-8000 King Seiko with a 4402A manual winding movement.

I've serviced this grade a couple of times before and it's went OK. Before servicing the watch was gunked up and a non-runner. Since servicing the watch is stopping maybe once or twice a day with the second hand between about the 28 and 32 second mark. Giving it an extra bit of torque by winding will start it off again.

I initially thought it was the second hand touching watch crystal, but I've ruled this out by placing some tape inside the crystal to simulate it being lower, and there is still lots of clearance with the second hand.

Thinking maybe it was gunk somewhere on the fourth wheel teeth stopping the second hand, I cleaned and inspected the wheel which seems fine.

Independent of the position of the second hand relative to the minute hand it will stop around the same point, so I'm assuming it's not something to do with the minute wheel...

Any ideas much appreciated! this has me well puzzled.

Edited December 21, 2022 by JBerry

[Nucejoe]

I remove the sweep hand , as its tube can be rubbing.

The sweep arbour itself  ( if bent )  might rub.

Sweep arbour's lower pivot or its relevent jewel and arbours end shake should be checked anyway.

Rgds