Problem: Install a new brake cylinder / clutch master cylinder and Connect the outlet pipe, then Add DOT3 brake liquid to push the rod. But the brake cylinder/ clutch cylinder is hard to continue output liquid - NOK Root Cause: Residual Air in bore inside & outlet pipe will hinder the piston moving and brake liquid flow easy and smooth. And without enough pressure, it’s not easy get rid of the Residual Air in bore inside and pipe. Solution: 1.Get rid of the Residual Air from bore and pipe as much as possible. 2.Suggest use Flare pipe interface match to our product outlet inverted flare seat better, avoid to Residual Air as much as possible. Get more information from https://www.compass-autoparts.com/ .