Larry Jewett
September 1, 2001
Contributers: Larry Jewett

There are few elements in automotive development that haven't been subjected to technological advance. Often, this "new and improved" way is truly better. It is probably best realized when one takes a look at brakes.

We've discussed many elements of modernizing the braking components throughout the years. Each year, the industry trade shows offer these new and better ways to help braking power. It's an ongoing area where there appears to be no end in improvement.

New materials and chemical compounds have been at the forefront. Better understanding of the physics involved have played a key role along the line.

There are many ways you can improve upon what was once a good idea. Many good ideas can be made better.

Some of the changes you'll need to make in a braking system can be brought about by parts that are simply beyond their expected usefulness. Other changes may be necessitated by a change in use, i.e., going from a sedate street car to a mean racing machine. It's important to understand the best formula to get the stopping power you require.

Disc-Brake Conversion
One of the most common moves by car owners is the switch from drum brakes to disc. This conversion has a number of advantages, with safety being right in the forefront.

Since the front brakes tend to do as much as three times the work of the rear brakes, the front end gets plenty of attention. Today, cars still come with front discs and rear drums, but you can make the move to four-wheel disc brakes with ease.

Front conversion kits are offered as complete units. In most cases, you can remove the old drum-brake setup and bolt on the material provided. Most will have superior calipers to provide greater clamping force. This is easily one of the best improvements to be considered.

Drum Brakes
If you have no desire to put disc brakes on the rear, you can always upgrade the drums. "We have bolt-on kits to give you bigger stopping power in the rear," says Jim Inglése of Cobra Automotive. Sizes of the kits are 10x1 3/4 or 10x2 inches. There is also a 10x2 1/2 kit that has recently become available. An 11x 2 1/4-inch option for the stock 9-inch Ford with the standard axle is being developed. This kit will not require changing tube ends and should provide greater stopping power.

Master Cylinders
This is an area that invites trouble today. While satisfactory in the '60s, the single master cylinder just doesn't hold up. "If you want to drive your car, you need to change the master cylinder," says Carmen Anastasio of Master Power Brakes. "They may be good enough for around town, but not for the highway. It's a step to better safety if you upgrade to a dual master cylinder with power brakes."

"These were suicide cylinders," echoes Inglése. "When they failed, you could lose the entire system."

The dual-reservoir master cylinder nearly eliminates the threat of total failure. One reservoir handles the rear brakes and, should it fail, the other, which services the front brakes, will be functional.

Power Boosters
Once an option on the cars of the mid-'60s, it's tough to imagine life without it. Power boosters have become a "must" for most interested in braking upgrades.

A potential downside to a power booster comes in mounting, since it often pushes the master cylinder precariously close to the shock tower. Bracketry developed by some of the companies has eliminated that problem.

Master Power manufactures its own power boosters for many different types of Fords. The booster uses atmospheric pressure to assist in pushing the master cylinder piston. Inside the power booster are two chambers separated by a rubber diaphragm. With no force, there is vacuum on each side. When the brake pedal is applied, the rod opens a valve to admit atmospheric pressure on the firewall side, causing the diaphragm to push a piston and apply power assistance to the master cylinder.

Proper installation of a power booster can lead to greater braking efficiency.

Wheel Cylinders
"Wheel cylinders are the first thing you need to look at," says Jim Inglése. "They tend to leak. Leaky rear-axle seals can cause malfunctions. They can lock up the rear wheels, so pull the shoe and check the linings."

You can rebuild your wheel cylinder, but the best solution is replacement. This gives the best performance from the seals, cups, and pistons.

Brake Fluid
The "blood" of the brake system is often misunderstood. It can truly affect the performance of the entire braking system.

High-performance enthusiasts are getting the gist of brake fluid quicker than the average consumer. Those who go fast need to stop quickly. Each time they brake, they put their faith in the system working properly.

"Racing fluid meets DOT (Department of Transportation) standards and has other processing for low aeration and low viscosity. You don't want the fluid to get air in it (aeration) when agitated," says Carl Bush of Wilwood Engineering. "Air makes it compressible and slow to work. Brake fluid will absorb moisture from the air and lower the effective boiling point.

For standard everyday use, a DOT 3 brake fluid is suitable. Heavier vehicles, like trucks, will use a DOT 4. There is also a DOT 5 silicone fluid, which isn't necessarily better in the progression, but involves a different material and, hence, a different designation.

"We recommend you change your fluid once a year and we recommend DOT 4," says Anastasio. "The fluid should be amber. If it's dark brown, it's contaminated. If it's black, it's burning up."

Brake Lines
In order for the fluid to do its job, the conduit from one end of the car to the other has to be free flowing. While there is certainly plenty of attention to the moving parts, the brake lines hold an important key.

"Inspect all your steel brake lines," says Inglése. "Those lines are running all along the car and they are subjected to the weather and the road. Steel lines can get rusty and leak. When we bring a car in for service, we like to replace the lines. We use stainless steel for our replacements."

Proportioning Valves These items need to be serviced or rebuilt. A bad proportioning valve can cause the rear brakes to lock up with pressure misapplied.

It's another area of misunderstood application. Anastasio notes a proper valve can take the "dive" off the front end of a car during braking. "It holds off the front brakes for a split second, allowing the rear to come in first," he said. Master Power valves come with a built-in residual pressure valve. In case of a lost line, the fluid will be shut off to that end and directed to the working part.

High-Performance Applications
The need for a high-performance racing car will be different from a daily driver. Wilwood Engineering directs plenty of attention to the sport end and has researched product to address the need.

"Our systems are based on car weight as much as speed," says Bush. "Our light-duty kits will fit the Pinto with the Mustang II suspension. We have kits for musclecars that will fit on stock spindles, and drag kits will come in light, medium, and heavy-duty.

In simple terms (call Wilwood for the best application), light systems will go on cars less than 2,400 pounds with rear disc brakes. These kits will take anywhere from 35 to 50 pounds off the front wheels. Medium kits are for cars in the 2,400 to 2,800 range, while the heavy-duty units are for cars weighing 2,800 pounds and up, especially those toting an iron big-block. The heavy kits are good for street and strip machines.

The development of man-made compounds has had a direct impact on the brake pad. The source of stopping friction, the brake pad continues to utilize material to best suit its needs.

Original brake-pad materials are hard to acquire and generally do not do the job as capably as today's materials. The asbestos pad has been replaced with materials of the carbon fiber family (such as carbon Kevlar). Pads need to be visually examined for wear and need of replacement.