- 1). Locate the brake line that you want to tighten on the vehicle using a flashlight. To tighten the fitting, you must rotate it counterclockwise. Although this seems obvious, depending on your position in relation to the fitting, determine which way that is so you don't loosen the fitting accidentally.
- 2). Slide the line wrench over the fitting on the brake line. The line wrench must fit tightly on the fitting with no play whatsoever--if the wrench has some room between it and the fitting, change to the correct wrench; otherwise you risk rounding off the fitting.
- 3). Push or pull the wrench to turn it counterclockwise until you can't apply anymore pressure. Once it's in place solidly, test the brakes and make sure there are no visible leaks.