Check whether the brake lever feels loose or pulls to the handlebar
Inspect brake pads for wear, glazing, or contamination
Replace worn or damaged brake pads
Clean brake pads and rim or rotor with isopropyl alcohol
Tighten loose brake caliper, brake lever, and cable anchor bolts
Check brake cable for fraying, rust, or damage
Replace damaged brake cable and housing
Adjust cable tension using the barrel adjuster
Center the brake caliper over the rim or rotor
Align brake pads so they contact the braking surface evenly
Set brake pad toe-in if needed
Make sure the wheel is seated properly in the frame or fork
True the wheel if the rim is rubbing the brake pads
Tighten or replace loose rotor bolts on disc brakes
Check hydraulic brakes for fluid leaks
Bleed hydraulic brakes if the lever feels spongy
Replace contaminated brake pads and clean the rotor if oil is present
Test the brakes before riding
Repeat adjustments until the wheel spins freely and braking is strong