The Stovebolt Site Forums The Shop Area Driveline Master Cylinder fittings

I am trying to replace the original fitting on the master. It seems to have an unnecessary port I want to eliminate.
I have found a fitting that seems to be the same size. Will this work?
The original had copper washers. I see the grooves on the new master for the same, but not on the replacement fitting I hope to use.
If this wont work, can I take the original fitting apart and install a new copper washer? The block spins easily, but the 2 parts don't seem to separate.
Any guidance appreciated.

That is a Banjo fitting. You can replace the washer. I would put the fitting bolt side up on a piece of wood and put a socket over the hex as if you were going to screw it down. You can then tap the socket lightly and the body of the fitting should move down. You can then replace the copper gasket with a new copper gasket.

The two fittings use entirely different sealing mechanisms. The original fitting is designed to seal using a soft copper gasket that crushes to create a pressure-tight connection. In contrast, the new brass fitting is an inverted flare type. This design relies on the precisely-machined flared end of the brake line seating perfectly against a matching flared surface inside the fitting to create its seal.

Because these designs are fundamentally incompatible, I have serious doubts that the new fitting would seal properly. A leak in a brake line would lead to a complete loss of hydraulic pressure and, consequently, a total failure of your brakes. Given that this is your only way to stop the vehicle, attempting to use this incorrect part would be extremely dangerous. I strongly advise against it.

The bolt / fitting could be held in by the port plug, pull it out before going after it with a hammer, JUST IN CASE. The port maybe for a brake light switch activated by pressure.

I don't think that the banjo bolt is held in by the side port plug nor is it for a brake light switch. That's there for a brake line fitting with inverted flare in the port.That plug was installed by someone who replaced the brake line that was there with the tee just downstream of the line coming straight out of the master cylinder. This was discussed in THIS THREAD started by jmoore. As far as getting the banjo bolt out of the fitting, the copper washer closest to the master cylinder has extruded into the threads of the bolt and is holding it in place.

Pound out the bolt from the banjo. Replace the copper washers. They are a one time use only item. At least they should be.

I got it apart and cleaned up.
I will obtain new copper washers and reuse the original fitting.

Thank you all.

Good job, and thanks for the follow up!

My shop broke the hollow bolt shown above that goes through the brass block and has a female inverted flare on the back side. Neither he nor I can find it anywhere. I guess we could put a master cylinder adapter with the inverted flare into the MC then a short piece of brake line to a Tee that the two lines could hook into. Any other suggestions would be appreciated.

Calll this company and see if they can help you.

Specializing in antique, vintage, classic, obsolete, unique and hard-to-find brake parts, bonding, riveting, rebuilding, drum and rotor machining, custom made brake hoses

Brake Materials & Parts Inc
800 Sherman Boulevard,
Fort Wayne, IN 46808
260-426-3331
https://www.brakematerialsandparts.com/

Thanks Otto, I will contact them and my sister lives in Ft. Wayne!

I would try posting a parts wanted ad in this forum. There are allot of ‘Bolters that replace the MC with a dual MC that doesn’t use that bolt, and just may have one left over.

Phil - He's already got one going HERE.

I contacted Brake Materials & Parts in Ft.Wayne, IN. and they had a used bolt of the correct size. They also suggested I buy the brass block too since it could be damaged, which I did. Unfortunately the side hole was the wrong size, but the shop had an adapter. All is good now. Thanks for the suggestion!

Those guys are great. I'm glad you got you got the parts to get your truck back together.

Thanks, I'm glad to be driving the old truck again. Amazing how one little broken bolt in the wrong place can completely incapacitate the truck! Usually you can find just about anything for those old AD trucks but that MC bolt is very rare. I missed the old truck, I have had it 36 years, half its life and half my life (It's a 53 and I'm a 54 model).

How long was the truck in dry dock?