Here is one of the numerous ways to go about mounting a hydraulic master cylinder on a model “A” Ford. This will allow you to then put 40 ford or some other type of hydraulic brakes onto a Model “A” rather than the original mechanical braking system.

Here is how to mount it:

***Note: You may need to shorten the rear radius rods or make sure the master cylinder will clear them.***

Relocating the Brake Pedal Arm:

First you will need to move the little arm on the brake pedal to the bottom rather than the top of the pedal. This will make the brake rod be pushed toward the back of the car when the pedal is depressed rather than pulled forward.

As you can see the arm that the bolt is through is now pointing down on the underside of the pedal rather than facing up on the top.

***Note: Be sure the arm will clear the clutch mechanism through the full range of motion of both the clutch and brake pedals.***

Building the Mounting Bracket:

Now you can build your bracket for the master cylinder. This will mount on the back of the center cross-member. To build this I used 2″X3″X3/16″ angle iron with the 2″ side cut to 3/4″ (the size of the lip on the bottom of the cross-member). I then marked the holes to drill for the master cylinder placing them as close to the top of the bracket as the cross-member would allow (to keep the brake rod straight).

The holes you see in the top are simply there for more surface area to weld.

Attaching the Bracket:

Now you can weld the bracket in place making sure to check that the brake rod will go straight from the pedal into the master cylinder.

Making Your Brake Rod:

***Note: Be absolutely sure that the rod you make can and will not bow in the slightest under extreme braking conditions such as slamming on the bakes. If it bends the brakes will no longer function.***

Once the mount has been welded in place bolt the master cylinder on and make sure it is level and in the right place. It is now time to build the brake rod which will run under the cross-member and into the master cylinder. To make this measure the distance from the brake pedal arm (in the “no brakes applied” position) to the master cylinder. Also measure how far the rod goes in before it actually begins to move the master cylinder insides. Add these together and you have the length of the brake rod you will need to make. I made mine out of an old rod I had and the end piece of the rod my master cylinder came with welded together. I added a turnbuckle with a jam nut for final adjustments (this can be seen in the first picture).

Final Assembly:

Now you can bolt the master cylinder in and hook up your brake rod and give it a try. Hopefully everything has gone smoothly and it all works. Now you can move on to the rest of setting up the brakes.

These instructions are for informational purposes only. If you decide to use them for anything I am in no way responsible for anything.

6 Comments to “Model "A" Master Cylinder Mounting”

1. Charlie Stephens — April 29, 2008 @ 10:45 pm
   

   Miles,

   The best way to illustrate what I am saying is a quick experiment. Go into the bathroom and get two rolls of toilet paper and the rod that you mount the paper on. The rod will be the pin and the inside of the paper roll will be the inside of the lever on the brake pedal. Insert the rod into the roll about half way. Push the rod to simulate the push on the brake rod. You will see that the force will be at two points. A similar situation will occur between the pin and the fitting on the end of the brake rod. These two points will carry the entire load and wear rapidly. Now support both ends of the rod with a roll of paper at each end. The load will be carried on a line. If you look at the brake system on a Model A you will see that wherever a pin is used on a clevis it will be supported on both sides with a fork shaped fitting.

   Charlie Stephens

   [Reply]

   miles reply on May 1st, 2008:

   Now I understand. I will add this to my setup.
   Thanks for the info,
   Miles

   [Reply]

2. Charlie Stephens — April 28, 2008 @ 4:19 pm
   

   Miles,

   Another thing I assume you intended to correct before you finished is the fitting at the end of the brake rod attaching to the lever to the brake pedal. This correct fitting extends around both sides of the lever. The current one would produce problems in the future as wear occurs. Best of luck with your project.

   Charlie Stephens

   [Reply]

   miles reply on April 28th, 2008:

   I was actually just planning on replacing the bolt with a pin and leaving it at that. What is wrong with this setup?

   [Reply]

3. Charlie Stephens — April 26, 2008 @ 2:37 am
   

   Let me start by saying thanks for taking the time to post your design. I am concerned about the long rod between the brake pedal and the master cylinder. My gut says it would fail as a column in compression with the first hard application of the brakes. Any misalignment of initial bend in this rod would make the problem much worse. A larger diameter rod, possibly a tube would eliminate this problem.

   Charlie Stephens

   [Reply]

   miles reply on April 26th, 2008:

   I believe you may be right and I was planning on testing how the rod performs under rapid braking once I get the whole setup installed (lines and wheel cylinders) because as of now it works fine (however this is a dry cylinder with little resistance). I will most likely use a thicker grade 8 rod once the project is complete because of the bowing you discussed. I will add a note in the article to provide others with this information.

   Thanks Again For Your Concern,
   Miles

   [Reply]

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