At the end of the disc brake article I did last year, I noted that there was a better than average chance that the brake pedal swing radius wouldn't be correct for the newer master cylinder. When I did the brake upgrade on my 67 Mustang Coupe, that's exactly what happened. I checked into new master cylinders that would produce the appropriate fluid flow and got a major case of sticker shock. Not only were they expensive but also unique to the application and only available from the specific supplier of the part. That won't do you much good if it fails at a track out of state in the middle of a driving school or race week. I think there's a better way and it uses a stock, over the counter 1977 Ford Granada master cylinder that you can buy at any one of several national auto parts chains. If the car was an automatic, it would be a piece of cake, it's a 4 speed so it's slightly more complicated. Hey, solving the hard problems, that's the fun part.
Here's how to do it.
| The first thing to do is find the swing radius for the brake pedal and master cylinder combo you're using. In the case of the Granada, it's 4.125 inches. That's about double the 1967 Mustang swing radius. The Mustang brake pedal swings on the shaft of the clutch pedal. Changing the brake pedal swing radius without changing the clutch pedal swing radius is the hard part. |  |
| In the pictures to the right, the small holes (arrows) are the new holes for the brake pedal pivot assembly. The larger hole below them is the original mount hole for the white metal castings that house the plastic bushings that the clutch shaft rotated in. When you change the brake pedal radius, the pedal arm must pass the clutch arm shaft. That's the challenge. |  |
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| In the picture above, a steel bushing was added to the assembly to support the clutch rod. The rod will be cut slightly longer than the bushing and drilled to accept a pin to hold the clutch pedal assembly in place. The brake pedal will swing through the opening to the left of the clutch pedal bushing. The outside of the hanger assembly is re-enforced with 1" square tubing to handle the additional torque that will be applied since only one side of the assembly is required to support the entire pedal load now. | In the picture above, a gusset is added to the bushing for additional strength. The square tubing is welded to the three sides of the hanger. A small rectangular relief hole is cut into the top of the hanger assembly for brake pedal arm clearance. The top of the brake pedal arm is too close to the top of the hanger to swing without interference. |
| The picture to the right shows the assembly with the brake pedal installed. Note the weld where the Granada pedal and the Mustang pedal are joined. This insures that the 67 pedal position is maintained in it's original position, aligned with the clutch pedal. |  |
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The picture to the left shows brake and clutch pedal assemblies installed and the tight clearances (arrow). The upper bushing is the brake pedal mount and the lower bushing is the new clutch pedal mount. Co-existing in perfect harmony. The Clutch pedal swings on a 2" radius and the brake pedal swings on a 4.125" radius. |
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| The completed assembly. Two pedal assemblies
with different swing radii in the same hanger. Pedal alignment is correct
and the assembly will accept the stock Granada master cylinder.
NOTE: This project required a lot of welding on components critical to your safety. If you're not skilled enough to attempt this on your own, have a certified welder do the work. If you attempt this yourself, be certain of the welds and have them inspected as a precaution prior to assembling and installing the pedal assembly. Safety first. |
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That's it for this time and there's much more to come. See you in the next newsletter.
Joe Quaranto