We haven't forgotten our truck project, although other things like: press events, vacations, parts ordering and a host of other diversions have delayed work for a few months. Anyway, we're back in to the swing of things and got to work putting some brakes into the old F1.
The first thing we needed to do was remove the rear brake drums to install all the brake components back there. The hubs are new and so are all the brake parts, so we laid out the shoes in the proper order (primary at the rear, secondary at the front) and selected the springs we'd use to hold everything together. Seem a little confusing? Why did we have to take off the hubs if they were new? Earlier on in the project we decided that it was desirable to have the chassis resting on its wheels, so we installed the hubs and brake drums without the brake shoes.
The parking brake cables had to be installed before anything else, so these were threaded through their holes in the rear of the backing plates. The ends were inserted in the levers that push on the rear shoes and the pivot pins were locked in place by a U-shaped clip. Once these were in place we could fasten the shoes to the backing plate through the use of rods, springs and spring-caps.
Threading the emergency brake cable through the backing plate.
Pins on parking brake pivot are held in place with U-shaped clips.
Now things got tricky, because all the parts had to be held together and mated to the brake cylinder and the reaction plate that travels horizontally between the shoes. With the rear shoe in place we could address the front shoe, but not before installing the square spring that tensions it against the reaction plate. Both shoes were fastened at the top with the springs that hold them, using the brake tool end that is designed for this operation.
This photo shows how the brake cable attaches to the emergency brake pivot.
Fastening the rear shoe to the backing plate, which is held in place by a small rod, spring and twist cap.
That left the bottom spring and adjustment assembly (the "star" wheel). We placed the star wheel adjuster — screwed to its minimum length — into position and then stretched the spring between the shoes. This spring-stretching operation is never easy, by the way, and required brute force.
With the emergency brake link just resting in place, along with the link spring, we will need to hold everything into place while installing the front shoe.
With the assemblies properly in place we put the drums back on and rotated the axles to make sure there was no binding or scraping. We'll adjust the brakes when we get the chassis on its wheels and fill the system with brake fluid.
After fitting the rear shoe, we inserted the pin/spring/cap to hold it into place, inserted the star-wheel adjuster and pulled the retracting springs into place.
The truck's brake lines were long rusted away, and that meant we needed to put new lines in. Also, since we'd modified the brake system to a dual master cylinder we had to make provision for independent lines to the front (through a "T" fitting) and slightly different line lengths all around.
We went to the local auto parts store and bought generic brake line in various lengths. We did so because pre-made line sets are too expensive (in our opinion) and it's kind of fun to bend lines anyway. We spent less than $20 for a handful of lines and a T-fitting.
The original T fitting that fits on the axle tube cleaned up nicely on our wire brush.
At the rear axle we selected one line and screwed it into its fitting on the cylinder. From there we hand-formed (that's bending in engineering language!) the line around the spring shackle, past where it will receive a hold-down clamp, and over the differential case to its T-fitting on the axle tube (we cleaned up the original fitting and mating hardware, of course).
Once that was in we ran a line from the other wheel cylinder in the same manner. It was a little bit too long so we created a loop in it to mate to the T-fitting. (We admit that if this were a show car, we'd most likely tidy things up a bit). All fittings were tightened and we then ran line from the flexible hose coupling along the frame rail to the master cylinder. That line was about a foot short, so we ran another line from the cylinder over to it and used a union fitting to connect the two.
Hand-forming the brake line over the differential.
The front wheel lines were next. First, we ran a short line from the master cylinder to a T-fitting below. Then we ran a line from the left front brake (flexible hose connection) down the frame and over to the T-fitting. We were careful to run the line down to the bottom of the frame rail because it has to run under the steering box.
Final placement of the rear brake lines.
The right front wheel line was run along its frame and mated to the T-fitting, thus completing the brake system hydraulic components. All fittings were tightened and made ready for fluid. First, however, we need to powdercoat the brake pedal assembly and mount it onto the master cylinder.
The '72 Mustang dual master cylinder requires an adapter for under-the-floor installation. Both master cylinder and adapter were purchased from Sacramento Vintage Ford.
The rear brake lines come off the frame rail to the master cylinder and we positioned the T fitting for easy connection to the front brake lines.
We also did some minor cleaning up and painting of the brackets, equalizing lever, and clevises that make up the assembly that connects the parking brake lever to the brake cables. More about that later.
The front and back brake lines coming into the master cylinder.
Onward and upward...