Ensuring that there is enough cable slack present so that the arm goes all the way back, and then pumping the brake lever has increased the clamping force - but it's still possible to clamp the brake full on and then rotate the wheel by hand.
Next suggestion?
Bleeding probably.
@Dammit started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
Ensuring that there is enough cable slack present so that the arm goes all the way back, and then pumping the brake lever has increased the clamping force - but it's still possible to clamp the brake full on and then rotate the wheel by hand.
Next suggestion?