For our rental business, we recently bought a bunch of 2019 Giant Talon 2 mountain bikes as replacements for 2017 Giant Talon 3s. The 2017 bikes have Tektro M290 Auriga brake levers, and we never had problems with them. The new fleet comes with Tektro M275 brake levers, and a significant fraction have gone soft. The calipers on 2017 and 2019 bikes seem identical, and this is only happening on the rear brakes. Attempts to bleed them have not been entirely successful. We called the dealer and they sent a Giant rep of some kind to our business who told us to adjust the reach? I wasn't there when he came, but we already did this to keep them on the road/trail, and we are now we need to bleed the brakes to keep them rolling. I read somewhere that the internal seals might be failing?Does anyone here have similar problems? If so were you able to fix them?Otherwise, I would like the Giant dealer to replace all levers with M290's.

OK this one https://www.tektro.com/products.php?p=257 ... looked up the service manual?

who has this brake?

As you saw , OEM parts picks change over time/...