A bleeder valve was a piece fitted into the master brake cylinder of a car. Without the bleeder valve, brake fluid would spill out onto the engine, causing the brakes to fail (17).
In 1967, the bleeder valve was removed from Roger Collins' car by his son, David (10). Roger's car crashed on his way into town and he falsely assumed the valve was removed by Burke Devlin, who'd recently returned to town (14, 17).
After the valve was found in David's room by Victoria Winters, David stole it back and ran away into town, where he went to Burke's hotel room (25-28). David planted the valve in Burke's couch, but later regretted it when he found Burke to be very friendly. Burke secretly found the valve and later produced it in front of Roger at Collinwood, after driving David home. He lied for the boy, claiming to have found it on the side of the road, but Roger and Vicki already knew it was David who had sabotaged the automobile (29-31). Elizabeth told Sheriff Carter that the valve fell off on its own, due to Matthew Morgan's carelessness, a story she later asked him to back up (32, 38).