1970 - 1971 Mopar Metering Valve Autopsy

This Kelsey-Hayes metering valve was originally used on a 1971 Dodge Challenger.The original part number is 3466157. The 1970 3466156 valve is similar, but it used a different mounting bracket. Original applications include 1970 and 1971 Barracuda, Challenger, Belvedere, Satellite, Coronet, and Charger with front disk and rear drum brakes. The same basic part was also used on 1968 - 1969 full-sized Ford police cars and taxis (part number C7VY-2B161-B), 1970 - 1971 Ford Galaxies and Thunderbirds (part number D0AZ-2B161-B) and 1968 - 1972 Ford F250 and F350 trucks (part number C8TZ-2B161-A). It's purpose is to slightly delay the application of fluid pressure to front disk brakes so that they don't engage before rear drum brakes engage. It is sometimes also described as a hold-off valve.

The brass body is marked with "KH"(Kelsey-Hayes), "M", "F", "F", and a "46 1" date code. There's supposed to be a rubber dust cap on the nut to seal the opening where the rod protrudes from the valve. This valve is missing the dust cap.

I decided to disassemble it to see if it's rebuildable. Follow along as I tear it down!  Tools needed:

  • 20mm 12-point socket
  • Pliers

Start by removing the nut at the end of the valve. Look closely and you'll notice that it's not a standard six-point hex nut. You can use a 20mm 12-point socket to remove the nut without damaging the edges.

With the nut removed you'll be able to see a brass cap at the top of the valve assembly. Remove it by gently pulling on the rod using your pliers.

Extract the small brass "hat" found on the end of the rod beneath the valve assembly.

There's not much to it, is there? This type of valve can leak when the black rubber seal shown above (visible to the right of the spring) is compromised. The spring-loaded assembly can be disassembled further (see my rebuild article for a view of the disassembled parts) by removing a small side-mount external retaining ring that fits on the rod to keep the spring compressed. Interestingly, this internal assembly also appears to have been used in the cast iron Kelsey-Hayes combination valves that were used in the 1970s.