Dual Master Cylinder Conversion

[Jeff W]

I didn't use the adapters. I cut the flare off of the end of the 3/16" tube and removed the existing tube nut, put on the correct size flare nut and re-flared the tube.

You have to get the correct size nuts for the 3/16" tube which is not easy to find.

The other thing to remember is that you need to do a "double flare" in the tube for brake lines.

The nut size is:1/2"-20 x 3/16" and 9/16"-18 x 3/16". You will need one of each.

This is the link where I normally purchase from, but I'm sure there are others:

http://www.ultrastang.com/products5.php

I feel using these right sized nuts rather than adapters makes for a cleaner installation and have less potential for leaks... on the other hand it requires a good flaring tool and some patience to learn how to double flare.

Oh... if you want to use the original style brake light switch, you will need to find the fitting with two of the 3/8" inverted flares and one with 1/8" NPT.

like this:
http://www.summitracing.com/parts/aa...0137/overview/
I think the specs are written wrong - he tube size should be 3/16" but the nut is 3/8" for the inverted ends... unless I'm missing something.

For the T-fitting where you separate out for each front brake, all three have the 3/8" inverted flare.

Like this:
http://www.summitracing.com/parts/hdt-lf-020/overview/

I think both of your T-fittings are incorrect.

Your lines look correct and will become conical (inverted flare) when you tighten them onto the matching fitting.

Thank you for doing this upgrade!

Kenny, Roger or anyone, please correct me if I have any of the sizes wrong. I think I wrote the sizes on the club parts bin before I handed it off.

[Luva65wagon]

I was just looking to see if we'd posted images or something on this. Here's a PDF Kenny posted a couple years ago:

http://www.cometeastcarclub.org/PDFs...erCylinder.pdf

But the important thing to look for are that the fittings you use are internal flare and not pipe thread fittings (like you show in your pictures). If you have the old T with male 1/8" pipe and two 3/16" internal flare you can use this to add the hydraulic switch in the line - just need a 1/8" npt female/female coupler. I wholly recommend also what Jeff recommends for fittings to the M/C. Gotta be good with the flare tool though. Double-flares are not something to take lightly. You can use adapter fittings for a worse-case, don't care how it looks, non OCD install. Checking for leaks is essential no matter what your method of assembly.

I know there was more information on the site. If I find it, I'll post more.

[Luva65wagon]

The thingI noticed after posting the above link and is also mentioned in the next is that Dick mentions nothing about the 3/16 to whatever size thread fitting is in the M/C. This thread addresses this a little better:

http://www.rainierfalcons.com/forums...highlight=dual

[Jeff W]

Roger, are the tube nuts for 3/16" diameter brake line line actually 3/8"-24?

I think hey are but the more I look the more confused I become. I think it has something to do with the beer

[Jeff W]

Guess Ebay knows all:

http://www.ebay.com/itm/3-16-Inverte...-/390717387105

3/16" fitting has 3/8" -24 threads.

Also much cheaper than Summit.

[Jeff W]

Here are the adapters if you want to go that route -

BRAKE LINE ADAPTER FOR MASTER CYLINDER 1/2 20 male X 3/8 24 female:

http://www.ebay.com/itm/BRAKE-LINE-A...74a5c2&vxp=mtr

BRAKE LINE ADAPTER FOR MASTER CYLINDER 9/16 18 male X 3/8 24 female:

http://www.ebay.com/itm/BRAKE-LINE-A...09706b&vxp=mtr

[ew1usnr]

Hello, guys.

Thanks for the quick and detailed responses. That was great! It will take me a while to read through them thoroughly and follow all the links. I am surprised that the directions I have are so incomplete.

I'll track the needed parts down and will describe my progress with further updates and/or more questions.

What started this was Jeff's quote:

I bet if it wasn't covered up by the crumpled fender, you would still see the original single bowl master cylinder. I hope the driver/passengers are not badly hurt. This picture is a good motivation for all to upgrade to 1967 technology and install the dual master cylinder.

It kind of freaked me out.