Get yourself a good repair manual [ like Les Andrews or others]. These brakes are not like hydraulic brakes, these brakes have several adjustments and everything leading up to the adjustments has to be right before they will work correctly. To stop the pulling until you can really fix the brakes, try tightening the left adjuster a bit until the pull stops. Depending on what or which wheel is causing the pull will determine whether to tighten the front or rear.