Shimano ST-7S20 cleaning and lubricating because of resinous mechanics

ID: 181012

Description: Shimano ST-7S20 is a nice trigger for Shimano...

Steps:

  1. Loose the socket screw of the clamp with a 5mm hex key.
  2. Rotate the shift lever around 180° so you can see the bottom cover with the phillips screw.
  3. Tighten the clamp screw again with a 5mm hex key.
  4. Remove the phillips screw of the case.
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  5. Carefully lift the cover with your fingers.
  6. Remove the Cover.
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  7. If possible shift carefully threw all seven gears.
  8. Upwords and downwords shifting, if possible.
  9. Watch if something strange or special is happening. Focus on the pawls and springs. Does every pawl lock properly on time? Are springs damaged or broken?
  10. For me this pawl and spring was stiff and risinified. The powl locked very slowley like it was creeping.
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  11. Clean the gear of the shift lever of old and resinous grease.
  12. You can use brake cleaner or penetrating oil like WD40 or Ballistol with cloth or a brush.
  13. If you have time let absorb the cleaning agent over night.
  14. While cleaning switch gears carefully up and down so the stiff parts will get more moveable.
  15. If a pawl is stiff directly spray your penetrating oil on its pivot bearing.
  16. Important after cleaning: relubricte all important movable parts. I can recommand a combination of grease and oil.
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