Rebuild your proportioning valve and stop leaks. Kit includes 4 seals and a retaining ring. Note: Ford had two versions of proportioning valves on 65-66 - an early and late style. They are externally identical but different internally and the parts are not interchangeable. This kit is for early style proportioning valves. Not returnable if opened. To identify which you have, the earlier versions have a special bolt and removable washer. Later styles do not.