66 Dodge Dart upgrade Dual conversion help!

[66DartSedan]

Hi,

So it looks like I have leaking brakes.

Ive decided to upgrade to Dual Master Cylinder

Can someone out line, all the parts I will need?

 

[66durgederp]

Heres what I did on mine and its served me very well. 74 charger manual brake dual pot master, works with the factory pushrod as well, no need for the adjustable unit. 87 plymouth gran fury proportioning valve, and matched brakes from that same car. I did all brand new lines because mine were crusty. 10" disc in the front and 11" drums in the rear.

 

[66DartSedan]

Heres what I did on mine and its served me very well. 74 charger manual brake dual pot master, works with the factory pushrod as well, no need for the adjustable unit. 87 plymouth gran fury proportioning valve, and matched brakes from that same car. I did all brand new lines because mine were crusty. 10" disc in the front and 11" drums in the rear.

I ordered a 1970 Dual Master Cylinder ...the guy said Ill need adapters but Im thinking Ill just get lines as well, so i was hoping for a list of items I need to get

 

[slantsixdan]

The dual master cylinder swap is a very good idea. Get a new master cylinder, don't futz around with "remanufactured" garbage. Use a Wagner MC71258, Bendix 11323 or Raybestos MC36221. It'll bolt right in place of your existing single-pot master, and your existing pushrod will work. You'll need a distribution (splitter) block; this can be had used from any A-body with 4-wheel drums, '67-up, but probably easiest to get it new from Inline Tube. You'll need to run dual hardlines from the new master to the splitter block. Be sure to bend at least one fully-circular loop in each of them to let them flex. Steel line is standard and is a pain to work with; Cunifer is a lot easier (and better).

 

[66DartSedan]

The dual master cylinder swap is a very good idea. Get a new master cylinder, don't futz around with "remanufactured" garbage. Use a Wagner MC71258, Bendix 11323 or Raybestos MC36221. It'll bolt right in place of your existing single-pot master, and your existing pushrod will work. You'll need a distribution (splitter) block; this can be had used from any A-body with 4-wheel drums, '67-up, but probably easiest to get it new from Inline Tube. You'll need to run dual hardlines from the new master to the splitter block. Be sure to bend at least one fully-circular loop in each of them to let them flex. Steel line is standard and is a pain to work with; Cunifer is a lot easier (and better).

Thanks, according to Cunifer, i need to know exactly what I need before I call, what exactly do i need to ask for?

 

[Doug.S]

Thanks, according to Cunifer, i need to know exactly what I need before I call, what exactly do i need to ask for?

Hey 66DartSedan,
I just did the dual pot master upgrade with my 64 Dart. I was able to accomplish this task with much help from this forum. Before you call and start asking for parts, you need to determine how deep into the project you want or need to get.
You say that you have leaking brakes. Does this mean you have a leak at a wheel cylinder, or did a line break and now you have no brakes at all? If you have a leak at a wheel cylinder, you should check all of them.
When I brought home my new ride a couple of months ago, I knew in advance that I would be replacing every part of the brake system. So, I ordered all 4 wheel cylinders, brake line similar to what Slantsix Dan recommended (S.U.R.R. I believe), a dual pot master cylinder, fittings, all the brake components (shoes, and new hardware kits), dual master conversion brass block from Inline Tube, and some Dot 4. I took one day and went through the entire process. You could take less time and throw in the dual pot and use the existing brass block with a plug in it for the original rear line fitting. Then they run the rear line direct. There was a great article that I read a couple of times at earlycuda.org linked here Early Valiant Barracuda Club - dual master cylinder. If you have never done this before, you should wait to unbolt the existing master cylinder until you have used the brake pedal to pull the push rod out. A quick hard pull is all that it takes to get the original rubber grommet to let loose. Much easier than putting the single pot in a vice and pulling. Don't forget you will have to adjust your brake light switch when this is all said and done. Search dual master cylinder in the top right of this page. Many great articles.
Good luck and enjoy the better braking experience!
Doug

 

[66DartSedan]

Hey 66DartSedan,
I just did the dual pot master upgrade with my 64 Dart. I was able to accomplish this task with much help from this forum. Before you call and start asking for parts, you need to determine how deep into the project you want or need to get.
You say that you have leaking brakes. Does this mean you have a leak at a wheel cylinder, or did a line break and now you have no brakes at all? If you have a leak at a wheel cylinder, you should check all of them.
When I brought home my new ride a couple of months ago, I knew in advance that I would be replacing every part of the brake system. So, I ordered all 4 wheel cylinders, brake line similar to what Slantsix Dan recommended (S.U.R.R. I believe), a dual pot master cylinder, fittings, all the brake components (shoes, and new hardware kits), dual master conversion brass block from Inline Tube, and some Dot 4. I took one day and went through the entire process. You could take less time and throw in the dual pot and use the existing brass block with a plug in it for the original rear line fitting. Then they run the rear line direct. There was a great article that I read a couple of times at earlycuda.org linked here Early Valiant Barracuda Club - dual master cylinder. If you have never done this before, you should wait to unbolt the existing master cylinder until you have used the brake pedal to pull the push rod out. A quick hard pull is all that it takes to get the original rubber grommet to let loose. Much easier than putting the single pot in a vice and pulling. Don't forget you will have to adjust your brake light switch when this is all said and done. Search dual master cylinder in the top right of this page. Many great articles.
Good luck and enjoy the better braking experience!
Doug

This is the back left wheel, i took a photo last night

 

[66DartSedan]

This is the back left wheel, i took a photo last night

 

[66DartSedan]

This site is having trouble showing my photo, heres a link:

 

[Doug.S]

Looks like there is a leak at that fitting? Usually when I see leaks at wheel cylinders, they are inside the drum around the pistons and dust boots. The repair necessary there could be as simple as a new run of 3/16 brake line from the brass block on the rear axle to the wheel cylinder. Or a line run and a new rear wheel cylinder. Both rear wheel cylinders on your car are same, so ordering one is not difficult. If you order front wheel cylinders keep in mind they are different for each side.
Please before you fix one little piece of this puzzle, you may want to investigate your entire situation. There are 6 pre-bent steel lines on your car from the factory, a single pot master cylinder, 3 hoses, 3 brake hose clips, a brass distribution block on the front frame rail under the master cylinder area, a brass distribution block on the top drivers side of the rear axle, and 4 wheel cylinders. If you want to piece in some fixes for these items, find which items you need. If you want much safer conditions replace everything and you know it is of good quality and safe.
You can order all the lines pre-bent in steel or stainless steel from Inline Tube. Check here 1966 Dodge Dart A Body Dual Master Conversion Complete Brake Line Kit Stainless | eBay. You need the new brass distribution block for the dual pot conversion here 1965-66 Mopar A B C Body Dual Master Conversion Distribution Block Tee Valve | eBay. Slantsix Dan recommended some great dual pot master cylinders. I used the Raybestos one. Worked great. As a matter of fact, I ordered everything else that I needed from Rockauto.com. They carry that master cylinder and all of the hoses, clips, wheel cylinders, brake shoes, hardware kits, and even the tools. You will need a service manual or you need to take pictures of the existing brake hardware set up. Make sure you get it put back together the way it came apart and use line wrenches on all the brake lines or you will round off those fittings. Good luck.
Doug

 

[Jayman62]

Going to be doing a dual master replacement soon on my 66 Dart and had some specific questions. I also want to replace all the hard lines but don't want to bend my own lines and was thinking of buying the pre-bent lines.

I understand I have to run from the rear distribution block to one of the outs of the master cylinder but how do I do this? Do I put in an adapter where the rear to front line ends (at the front dist. block) or does someone make a complete rear block to master cylinder line?

Also I realize that I need to utilize two of the ports on the original front distribution block, and block the original rear outlet on the block, but if I use pre-made front lines will they physically fit or will they may need to be extended.

And finally, if I do decide to make my own hard lines, is copper the way to go or do you all suggest a different material, and what about the spiral metal jacket used on some parts of the lines, does that need to be replicated in some fashion?

Thanks and sorry for all the questions.

 

[toolmanmike]

"is copper the way to go"
Never use copper. It's too soft and can blow out. Talk to your parts store. Steel (not stainless) or the new easy to bend metal. It's a green color and is easy to work with. All flares are double flare. No single flares for brake lines.

 

[JDMopar]

You can also buy copper clad steel lines, to make it less prone to rust. I usually buy a 25' roll at NAPA to do a car. I have looked for the spiral spring wrap stuff myself, and haven't had any luck. Admittedly....I'm not the best Googler in the world!