More Brakes

The Sunbeam arrived without functioning brakes, and one of the first repairs was to rebuild the brake hydraulic system. This step, covered in the first blog, entailed replacing all of the rubber seals in the master cylinder (the part connected to the brake pedal that converts foot pressure into hydraulic pressure), the front wheel brake calipers, and rear wheel cylinders (which convert hydraulic pressure into stopping power). We did not touch the steel brake lines, which carry the hydraulic fluid from the master cylinder to the wheels because they looked to be in good shape.For peace of mind, however, I decided to replace the steel lines in case they were rusting  from the inside.

Steel brake lines are tubes that come from the parts store in long, straight pieces that need to be bent and cut to the proper shape. In the picture above  you can see a new, straight length running diagonally on top of the box and also an old line from the car that was bent to fit between the front wheels and around the engine. I used the box to catch brake hydraulic fluid from old line.

In the next picture you can see new line next to the old. I used special pliers (with the blue handle) and a tubing bender (on the bottom of the box) to shape the brake line without crimping it. Because the line is hollow, it needs to be formed around a curved tool. Otherwise, it will kink, and the inner passage for the hydraulic fluid will collapse. This particular  section was easy to form because it could be removed from the car in one piece.

The end of each brake line is flared into a bubble or horn shape to make a leak free connection. The picture shows two examples of a flare. The short piece is the flare I cut off of the old brake line. The longer piece has the new flare, with a special brake line nut behind it. The nut attaches to the next part in the system and presses the flare onto it. If the flare is well formed, the joint will not leak.

The Sunbeam’s brake system includes several  branches or “T” connections to route hydraulic fluid from the master cylinder to the front and rear of the car and then to the left and right wheels. In the example to the right, fluid from the master cylinder enters the “T” fitting from the right. The downward branch goes to the rear wheels, and the left branch to the front wheels. The car’s braking system now has all new or rebuilt parts.

Someone familiar with Sunbeams may notice a nonstandard black box on the firewall, just under the brake line. This is a fuel cutoff switch that interrupts power to the fuel pump if the car is in a accident. Newer cars have these safety devices, and this one came from a Ford via Ebay.