Originally Posted by
timtak
I am missing the tiny bit of metal that attaches the up shifter of my right 105 (5700) metal lever to the back of the brake handle. It is about the size of a fingernail with a hole in the centre that traps the metal gear lever into a grove in the back of the brake lever.
It is shown in this Korean language diagram.
My LBS said I would have to buy the whole right shift-brake lever assembly.
Time to find a new LBS who actually know something about bikes.
Any LBS should have looked at the Tech Docs -
SHIMANO Dealer's Manual / User's Manual look at the EV for ST-5700
From your description/image, you want Y6TH02000 R.H. Main Lever Support You should be able to order this part by any bike shop who stocks Shimano. It's here on Amazon as well
https://www.amazon.com/Shimano-10-Sp...=1&*entries*=0 or Rakuten
Shimano 105 5700 10-Speed ST-5700 R.H MAIN Lever SUPPORT R - Y6TH02000 - Rakuten.com