DEUCE BRAKE LINE REFERENCE GUIDE (Sizes, lengths, fittings)

[GASCANS001]

A nearly exact replacement for the 1988 airforce deuce is the Dorman M39477. It will be the same with the only exceptions being the reservoir will be labeled Dot3 (but dot 5 can be used since seals are EPDM), it will have slits in the reservoir cap seals to act as the breather, and it wont have the remote breather fitting installed (both of which you can add or modify on your own, but are only needed if you would be fording water deeper than the height of the master cylinder). These can be found online (such as Summit Racing).

In need of another one today! Did some research and found this thread. However, that part number is now unavailable. The updated part number (sold at O’reilly’s) is NMC23114

 

[peashooter]

M35A3 MASTER CYLINDER REPLACEMENT
Here are some options for master cylinder replacements on the A3 dual circuit deuces that are still available as of 2024. These will be high quality and have the correct casting, 50/50 split, and guts, but will come with a plastic reservoir that you need to remove and replace with the existing remote reservoir plate from the old unit. I think these have recently started being made in China so to my knowledge there are no longer any new USA made replacements.
-CENTRIC brand, model 130.83014
-Dorman brand, model M12000

A couple notes:
-Raybestos tends to do things different so if someone does a cross reference on these numbers and pulls up other brands they may not actually work correctly, such as Raybestos that will often have an aluminum reservoir that has a different bolt pattern.
-when putting a remote top (or reservoir) back onto a master cylinder, you will need to push the piston in about an inch with a large C-clamp. There are 2 valves that sit between the reservoir and the main casting body and the valves "tip" open when the piston is in its natural position. Once the piston is pushed in a little bit, then the valves will sit vertical and can move up and down on their own. If putting a reservoir or remote reservoir top plate onto the main body without first pushing the piston in, then you will bend the 2 valves as you tighten down the top plate/reservoir.

 

[Major Asstyrd]

This a great thread peashooter! If you are in Minnesota it would be a trek for you to go to the Camp Plymouth Military Vehicle Show and Swap Meet we produce every April in Plymouth, CA. We'd love to have a technical seminar on these subjects. This year we are featuring a Big Truck & Service Vehicle Showcase on April 20. If you want a vacation and have some California sites you want to see, fly into Sacramento, get a car, and come meet some truck owners first. Bring any technical info you want to share. The RV campground has a rec hall that is perfect for indoor meetings and has a screen for AV presentations. We put things like seminars and discussion groups on our published schedule.

I bring this up to also let others know about what's possible at this large event.