This document describes how to rebuild the 1970 - 1971 Mopar 3466156 and 3466157 brass metering/hold-off brake valves manufactured by Kelsey-Hayes using a new seal kit available from Muscle Car Research LLC. 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). Tools needed:
Note that this valve uses a special 8-sided nut to seal the end of the valve. You can use a 20mm 12-point socket that's available from any hardware store to install the nut without damaging the edges
The seal kit provided by Muscle Car Research LLC includes the following parts:
- Metering valve seal
- Retaining ring
Arrange your valve, tools, and rebuild kit on a clean work surface. Let's get started! The first step is to inspect the valve and make sure that the exterior is undamaged. Check the port threads for damage. Make sure the body is securely attached to the mounting bracket. A loose mounting bracket can be tightened up by lightly tapping the mounting studs with a ball peen hammer. If any of the brass port threads are stripped or damaged you're better off finding another valve. If your valve passes the exterior inspection you're ready to disassemble it and inspect the internal parts.
Disassemble the valve as described in our 1970 - 1971 Mopar Metering Valve Autopsy article. Soak the metal parts for a few hours in a container of liquid ammonia. Ammonia does a great job of softening tarnish on brass, but be careful of the smell! Remove the parts, flush with water, and polish with steel wool. Clean the bore of the valve with the cotton swabs and fine steel wool and make sure that the bore is perfectly clean - any dirty residue that lingers in here can cause a leak! Finish cleaning the parts using alcohol and cotton swabs. The bracket can be cleaned with a wire wheel or by bead blasting. Rinse with alcohol when finished. Lay out the clean parts and your rebuild kit.
Reassembling the metering valve starts with the rod and seal.
Lubricate the seal with clean brake fluid and slide it onto the end of the rod as shown below. It should fit snugly against the raised edge you see between the groove and the larger-diameter "barrel". The brass ring is installed next.
Lubricate the brass ring with clean brake fluid and slide it onto the end of the seal. it should fit snugly against the ridge on the seal. The steel cap is installed next.
Slide the steel cap over the narrow end of the seal. The spring, steel disk, and retaining ring are installed next.
This is probably the most difficult step in the process. Place the assembly in your bench vise with the exposed end of the rod pointing down and the seal resting on top of the jaws. You need to be able to push down on the steel disk to compress the spring far enough to expose the slot on the end of the rod. Compress the spring and push the retaining ring into place using small needle-nose pliers with a magnetic holder at the edge of the assembly. You don't want to lose the retaining ring if everything snaps apart suddenly! The steel cap should be installed with the dished end facing outward. The round rubber seal and brass cap are installed next.
Install the round rubber seal onto the end of the valve assembly.
Now we start installing parts in the body of the valve. Install the brass cap into the hole at the bottom of the bore with the raised side of the cap fitting into the hole.
Lubricate the valve assembly with clean brake fluid and push it into the body of the valve with the long end of the rod pointing out.
Install the brass disk over the end of the valve assembly.
Install the steel nut using the 8-sided socket or adjustable wrench. It should be just tight enough to keep from coming loose. Note that the Ford C8TZ-2B161-A valve uses a steel plug that held in place with a snap ring. Install the rubber dust cap if you have one (not shown since I don't have one) and your valve is ready to go!
Now you can reinstall the valve in the car and reconnect the brake lines to the valve. Start each line by hand as best you can to ensure that the fittings are threading in straight and smooth. Be careful - it's easy to cross-thread the fittings and damage the soft brass threads. Tighten each fitting with a flare nut wrench. You may need to tighten, loosen, and retighten each fitting multiple times to obtain a leak-free seal. Add brake fluid, bleed the brakes, and check for leaks.