Standard Gauge Repair Help!!

I have a 10E, 33 and 384E that need the brushes replaced on the motors. How do you change brushes and springs on these standard gauge locomotives?? I am good with postwar trains, but I am learning with standard gauge. Anyone know a website or know off hand or from experience how to change brushes and springs on these locomotives? I have all the tools I would need, but I am afraid to take it apart, because they are 80+ years old. Thanks.

You might, repeat might, find something of use here.

http://pictures.olsenstoy.com/searchcd2t.htm

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Thank you, there is only one way to learn how to do it. Gotta try someday. I am not paying $$$ to get brushes installed in my locomotives from a Hobby Shop. Thanks.