The V brakes on your Roadmaster bicycle are a very important part of your safety and comfort while riding. V brakes are designed to give you the maximum braking power possible, so as to stop the bike quickly and effectively when needed. Over time though, your brake cables will stretch and your brake pads will wear out, leading to a frustrating and unsafe ride. Rather than ride conservatively and uncomfortably, learn how to repair the brakes on your bike at home.
Inspect the front and rear brake pads for wear. If the pads appear thin or smooth, they will need to be replaced to ensure maximum braking power. Remove a brake pad from one of the brakes using a 10mm wrench and take it to your local bike shop and purchase a replacement for each one that is worn. To install the replacement pads, simply insert the mounting bolt of the pad through the brake pad slot, line up the pad with the rim, and tighten the included 10mm nut onto the mounting bolt to hold the pad in place.
Loosen the brake cable stop bolt of the front brake using a 10mm wrench. This will allow the brake to open fully, effectively "resetting" the springs inside.
Squeeze the brake arms so that the pads sit about 5mm away from the rim, then pull the cable taught underneath the cable stop bolt. Tighten the cable stop bolt to secure to cable in place. Give the brake lever a good squeeze to settle the cable and ensure the brake pads make solid contact with the rim.
Repeat this procedure to adjust the rear brake pads and cable. Now that the cable tension of each brake is set correctly, observe the alignment of the brake pads with the rim. Take note if either pad on either brake makes contact with the rim before the other.
Tighten the brake arm tension screw of the arm of the brake that holds the pad that touches the rim first. Use a Phillips screwdriver and adjust the tension screw in half-turn increments, squeezing the brake lever between adjustments. When both brake pads make contact with the rim at the same time, the brake is adjusted and you're ready to ride.