To fix a crack in a basement wall, clean the crack, apply sealer to the crack, fill it with urethane, and then test the crack. Be sure to protect your eyes and hands with goggles, and gloves respectively before attempting this task.
Cleaning the crack involves clearing it of any debris and loose concrete pieces by brushing it with a wire brush. Once the crack is free of the material, mix surface seal epoxy according to manufacturer's instructions, place the epoxy in various injection ports, and place the ports on the crack at 6-inch intervals, taking care to work from the bottom of the crack to the top. Allow a 10-minute epoxy activation time before spreading it over the whole crack. Allow about one hour of curing time before proceeding.
Next, wet the crack with water using a spray bottle to facilitate urethane expansion. Connect a mixer to a urethane cartridge, and fix the cartridge on a caulk gun. Working from the crack's lower side, use the gun to fill the entire crack with the urethane through the ports. As you apply the urethane, it reacts with water to produce foam, which occupies the entire crack. Allow the urethane to sit for one day, and water the crack to test it. A well repaired basement wall crack does not contain any unfilled spaces, hence it does not absorb water.