It's this :)

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Note added at 12 mins (2007-07-26 02:08:01 GMT)
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Once the motor is dry re-oil the motor bushings using a good bushing oil. If your motor seems to be loosing it's punch replace the brush springs with new ...
http://home.kc.rr.com/grayghost/tips/MotorMaintenance.html

An article entitled "Replacing Wind Motor Bushings" by John A. Tuttle, appearing in issue 1998.12.29 of the Mechanical Music Digest.
http://mmd.foxtail.com/Archives/Digests/199812/1998.12.29.09...

washers are not touching motor bushing and tighten down the screws. Remove the. paper and check that gears have some backlash in them and all feels free. ...
http://brpracing.com/images/sc18instructions.pdf

etc...

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Note added at 53 mins (2007-07-26 02:48:55 GMT)
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'Bushing' in relation to electrical motors: -

Mabuchi Electric Motor. The best way to gain power from these motors is to properly break-in the motor brushes and the bronze bushings. ...
www.rccartips.com/rc-electric-motor-tuning-guide.htm

Electric motor with self-adjusting bushing structure - US Patent 6965180 from Patent Storm. A bushing structure 10 is constructed and arranged to be ...
www.patentstorm.us/patents/6965180-claims.html

A bushing structure 10 is constructed and arranged to be operatively associated with a shaft 24 of an electric motor 22. The motor has a housing 30 ...
www.freepatentsonline.com/6965180.html