Dual Bowl Master Cylinder Conversion Non Power Drum Brakes OE Steel Kit Mustang 1965-1966

As we’ve said in many or our videos, technology has come a long way in the last 15 years, especially in the area of safety. If you’re going to drive your Mustang on the streets, safety should be a main concern, especially when adding or upgrading parts. The case of our ’65 Coupe, we’ve upgraded our lighting to much better LED lighting, and also added three-point seatbelts for increased safety. Today, we’re going to upgrade the brakes, in particular the brake master cylinder. On the ’64 through ’66 Mustang, the brake master cylinder is a single reservoir goes out to all four wheels.

If you had a problem with your brake lines at any of these wheels, you can actually lose your entire braking system. In ’67, Ford switched to a dual bowl master cylinder. It’s got a reservoir for your rear brakes, and a separate one for the front. This has become a very popular upgrade for the ’64 through ’66 cars. Today, I’m going to show you how to do it using our ’65 Coupe. We offer kits that will give you all the parts necessary to do a dual bowl master conversion on your early Mustang. Our ’65 uses drum brakes, so we’re using the ’67 through ’70 dual bowl drum brake master cylinder, which includes the push rod, which we may or may not need and we’ll get to that later.

The kit also includes both lines necessary, a plug for the port you’re not going to be using and a union to connect to your factory rear brake line. For this installation, you’ll need a 3/8-inch ratchet, 5/8-inch socket, 9/16-inch socket, six-inch extension, 9/16-inch wrench, 1/2-inch wrench, 7/16-inch wrench, 3/8-inch line wrench or a standard wrench will work, large flathead screwdriver and a flashlight.

We’re going to remove two lines from the distribution block to start the installation, the main line here and the bottom one here that goes to our rear brake. I’m going to make sure you get the correct line. In our case, it’s going to be this on right here and this one here. Once they’re both disconnected, then we can unbolt and remove our master cylinder. We’re going to start with the rear brake lining to the bottom one here. Carefully slightly bend that out of the way once it’s disconnected. Now, we’re going to take this applied plug and put it right in that port we’ve just removed.

Now we’re going to remove the front line that goes from our factory master cylinder to our distribution block. Before we unbolt the master cylinder from the firewall, we want to disconnect the push rod from our brake pedal. Underneath the dashboard you start by removing the harness that goes to your brake light switch. Unfortunately, you can’t see it on camera, but right behind the brake light switch my finger is touching is a cotter pin. Once you remove that cotter pin, that will actually separate the push rod from the switch and the pedal assembly. Then I’m going to unbolt the master cylinder and remove it.

There we go, we got it separated. Now that it’s disconnected from the pedal, we can remove the master cylinder from the firewall. To do that, we remove these two bolts down here. The top ones can stay. It’s just the two bottom ones that holds the firewall. We mentioned in the introduction that it comes with a new push rod you may or may not use. What you’ll want to do is measure the push rod that comes off the car. Make sure the one included is the same length. If it is, you can use it. If not, reuse the original one.

Unfortunately for my sake, but unfortunately for camera sake, this normally has to be punched out. Ours is broken. It came right out. That is probably not going to happen when you have this at home. What you’re going to want to do, put the bottom of this in a vice. With the push rod still installed … Let’s put it back in here so you can sort of see what I’m saying here. With this in a vice, you want to put a punch or something on this end and you’ll want to hammer it out. This usually is difficult to get out. Ours, like I said happened to be broken so we can’t show you. Again, put this in a vice. Put a punch through this end here, and just hammer until this push rod comes out. Then we’ll compare it with our new one.

As you can see, our factory push rod is longer. Make sure everything works properly with our brake pedal where we use our factory push rod. Now that we’ve decided we can use our factory push rod, we’re going to bench plate the master cylinder. With the push rod, we do offer adjustable ones. If you wanted to go with a new one, you can buy the adjustable one and measure it out. The factory one is going to work fine on our application. Now to bench bleed the master cylinder, you start by removing these two plugs. Install the plugs provided with the master cylinder.

Just tighten them up by hand. You don’t have to actually crank them down. Now, we’re going to put in our vice and bench bleed. I’m going to grab some brake fluid. We’re going to top off the master cylinder to start. You don’t have to bring it all the way to the very tip top but get close. What you want to do is grab a screwdriver. You can use the push rod, but a screwdriver is going to be a lot easier. You can put it where the push rod is going to go. Basically, what you’re going to do is just push in, get the bubbles out. Just keep slowly pushing in. Once you get all the air out, it will get nice and hard when pushed in. When you have a firm pedal, you know you have it right.

Once you only go about 1/8-inch or a 1/4-inch, you’re done. Before we bolt the master cylinder in, we’re going to install the push rod boot that’s included with it. Install the original push rod. The original push rod doesn’t have a clip on it, so it’s basically going to be held in place by the boot, but once it’s bolted on it will be fine. Line it up, and we’re ready to install. We put the cylinder down into place. Then bolt it on. Now we’re going to install the hard lines that are included in our dual bowl conversion kit. This line here with the block fitting is going to go to our distribution block, which is going to run our front brakes. This line here is going to go to your rear brakes.

I’m not going to promise you these are going to fit 100 percent. Your car could be up to 50 years old. If the lines were changed or the distribution block was changed, the fitting may be off a little bit, but it will definitely get you in the neighborhood with what we’re looking for. We’re going to start with the front brake line, which is actually going to go from the rear port on our master cylinder over to our distribution block. Basically, it will fit just like that. Once we tighten then at the distribution block, now we can tighten at the master cylinder.

On the rear line, the first thing we’re going to do is install the union that’s included with our kit. Then we can bend that back in the neighborhood where it came from over here. We’ll connect this to the master cylinder side first. What you’ll want to do here is basically get an idea where this is going to sit. If it faces downward like it should … Remember, we moved that rear line out a little bit. You just want to bend that carefully back towards where your connection is going to be to your master cylinder. The lines are flexible. They’re easy to bend. Just make sure you don’t kink it.

Now you want to hold the union while you tighten the fittings. Finally, we can tighten at the master cylinder. Now back under the dash, we’re going to reach back at the pedal. Once you get the clip in, reinstall the harness. You’re installation is finished. At this point, you want to check and make sure you have a good pedal. Because we bench bled the master cylinder, you should have a good pedal and should be good to go. If you do have a soft pedal, you want to bleed the brakes as normal starting with the line furthest from the master cylinder.

The dual bowl is an excellent safety upgrade, and as we showed it’s a pretty easy installation. Keep in mind, these lines are designed for factory lines. If the lines have been changed in your car, you may need some adapters to make it work. Overall, the installation should only take you around an hour. You’ll be back on the road in no time.