Thank you for your question.
I can understand wanting to replace the bobbin winder assembly.
The hardest part to replacing the bobbin winder is to split the two half's of the sewing machine front and back covers.
I have sent a picture of all the screw locations in the parts image.
You will need to start with the bottom plate and then locate and remove any screw that holds the outer case to the interior frame.
Once you get the covers off remove the snap ring to the bobbin winder and notice how the tension spring ends are attached so you can reattach the same way on the new one.
If you do not feel confident repairing this problem yourself, then you can have it repaired by a Sears technician. Here is a link that will provide the nearest drop-off locations:
Sears Home Services
I hope this will help.
Thank you for using Manage My Life.