Restoration of the disc-drum brake system for my 70RR included an NOS Bendix master cylinder/booster, new lines and wheel cylinders, and the original 3 element valve system: tee, metering, and proportional valves. Since I'm using DOT5, decided to take the valves apart to at least clean them up. Jules DAddio was a valuable resource for this resto. Bought the tee and prop valve rebuild kits sold by Scott at Muscle Car Research. Took some pictures along the way for reference if anyone else wants to restore their original valves.

Tee valve. Disassembly of the tee valve is well documented at the MCR website. Below is a picture of my disassembled tee valve with the MCR seal-spring kit. As noted on the MCR site, you must be very careful removing the hex brass plug on one end of the bore (far right in the pic). After soaking with PB Blaster and heating with a propane torch, I was able to <carefully> get it off without distorting the brass head. Used air pressure to remove the internals. Soaked the valve/parts in orange cleaner, then used a paint gun brush to clean the bore. Used a 3M fine Scotchbrite pad to finish cleaning the bore. Note that the bracket plating has worn off, so I'll need to remove the bracket to get it plated.


Prop valve. MCR also sells a rebuild kit (seals only) for this valve which was manufactured by Kelsey Hayes. The trick with this one is removing the bore snap ring. It requires snap ring pliers with some long, thin fingers. Had purchased a repro prop valve from Inland Tube before deciding to rebuild mine. Took it apart also to see how close the internals matched. Below is a pic of my orig (top) and the repro prop valves. The components are very similar, the pistons have a similar design and identical widest diameter (.42"). The bore diameters appear to be the same, approx .50" (difficult to get an exact measurement, the smallest fitting for my bore gauge was slightly too large). The orig valve is 1.868" long (along the bore), .008" longer than the repro. The orig piston is 1.468" long, .008" longer than the repro. Use your own judgement as to whether the hard bore parts will interchange. The rubber should interchange or, cheaper, buy the MCR kit. I used the same process to clean the bore - orange soak, bore brush, and fine scotchbrite.


Metering valve. AFAIK there is no rebuild or seal kit for this valve. The biggest challenge, on an OEM valve, is the octagon bore nut. Removal of this nut is easier, with less risk to damaging the nut, by using a special socket available here. Thx to Jules for the reference. Here's a pic of the socket and octagon nut.


I obtained a repro metering valve from Finelines to determine if I could use the seals to rebuild my original. Below is the orig (top) and repro valves with the bore assemblies out. Note the Finelines bracket is plated while the plating has worn off my original. Interestingly, a friend has an Inland Tube metering valve and the bracket is not plated. I'm planning to graft the Finelines bracket to my original. If you look closely at the orig valve you can see a rectangular punch mark left of the bracket. There is no corresponding mark on the repro. This was probably done to stake the nut once installed.

Used small vice grips to compress the spring portion of the piston assembly to access and remove the <very> small lock rings. The lock ring is just ahead of the white plastic fitting. Be sure to use a washer or some other means to protect the rubber seal if you use vicegrips to do this.

Here's a pic of the internals separated for each valve.

Dimensionally the internals appear very similar but there are some differences. The repro uses a standard 6pt nut instead of the octagon nut on the original. This certainly makes for easier disassembly but, besides the stampings, is a dead giveaway of a repro valve. The nut can be removed from the shaft (shown separate in the pic). The nut was initially stuck to the shaft on the orig valve. After some WD40 treatment, I was able to unstick the nut such that it would slide off the shaft. From the pic, note that the perforated fittings just below the springs are of similar design though one is metal (orig), the other plastic. The repro rubber fitting on top of the bore nut (external to the valve body) is substantially different than the orig.

Here are some comparative measurements: orig; repro
Bore diam: .687"; .687"
Shaft length: 2.062"; 2.055"
Valve body length (along bore axis): .89"; .90"
Valve body width: .82"; .88"
Brass disk diam: .685"; .685"

Below is a closeup of the "hat" fitting that goes into the bore first and fits in a small cavity at the bottom of the bore. The orig hat is a single brass piece while the repro appears to be 2 pieces, or perhaps a broken single piece??? I will contact Finelines to check this out. Plan to use the 2 repro rubber pieces to rebuild the orig valve. Again used the same process to clean the bore, except I had to use a quick blast of glass beads to clean the bottom cavity.


Update: Finelines states that the 2 piece cavity fitting is per design. I'll use my single piece for the rebuild. Reassembled the prop valve today, using the MCR seals. The orig piston was gouged a bit when removing the snap ring so used the repro piston/spring. As the MCR site states, reinstalling the snap ring is a bit of a challenge. I used a long thin screwdriver to "balance" pressure, with the snap ring pliers, against the spring while inserting the snap ring. Marked the shaft of the screwdriver to the depth of the snap ring bore slot so I'd know when I was at/near the slot.