[Editor’s Note: This article originally appeared in the April 2007 issue of Grassroots Motorsports.]
Out of all of the systems in a car, the brakes have to be the most important. A car that can’t come to a safe, sure stop has no business being on the road or track.
While today’s cars come from the factory with solid, capable binders, that’s …
1. Pick the Right Compound
It’s very important to have the right pads and shoes fitted to your car. They have to be matched to the way you drive and how much heat your brakes generate.
If you fit racing brakes to a street car, you can expect worse-than-stock performance from them—they’ll never get hot enough to generate the necessary friction for optimum stopping power. Likewise, street pads on a race car will overheat quickly (even catch fire) and won’t do the job, either. And bargain pads are anything but a bargain—they often work poorly no matter how they’re used.
2. Look for Leaks
If anything is leaking in your braking system, fix it immediately. Make a visual inspection of all brake components and look for wet areas—you should find none. If you can’t find leaks but you are losing fluid, you haven’t looked hard enough. The fluid is leaking somewhere—it doesn’t evaporate.
3. Bleed Them Correctly
There are a lot of ways to bleed brakes, and some are better than others. We’ve always preferred the two-person way: One person goes to each wheel and bleeds the brake according to the shop manual instructions, while another person works the pedal. Some people prefer power bleeders. Either way, if your brakes aren’t bled properly, you’ll always have a soft, spongy pedal with too much travel.
4. Make Sure They’re Assembled Correctly
If a car has had at least one previous owner, assume that someone with a lack of mechanical ability has touched the brakes. It’s very common to find incorrectly installed or assembled brake parts. With drum brakes, it’s common to see linkages or shoes installed backward. With disc brakes, calipers sometimes get switched side to side. Check a manual or a trusted Web site to make sure your brakes are correctly put together.
5. Adjust the Drums
Many older cars have at least two drum brakes, and many are not self-adjusting. After making sure the adjusters are not frozen, adjust the brakes so they just start to drag. If you get them too tight, you’ll know in the first few hundred feet of your first drive. If they’re too loose, you’ll find that your pedal goes too far to the floor. Properly adjusted drum brakes account for about 75 percent of the pedal’s feel, so spend some time on this.
6. Adjust the Parking Brake
Your parking brake works, doesn’t it? It’s also called the emergency brake for a good reason, especially on single-circuit brake systems, so make sure it not only works, but it is adjusted properly and releases properly. Stuck parking brakes can quickly make brakes feel and act funny, and they wear things out more quickly.
7. Check the Hoses
A visual inspections of flexible brake hoses is pretty easy—look for leaks and cracks, discarding any hose with either.
Sometimes hoses will swell as they age. To check for this, feel the hose as an assistant steps hard on the pedal. If you can feel much swelling at all, get a new hose. Another good test is to clamp each hose shut while an assistant steps on the pedal. If the pedal is much harder with the hose clamped, it is probably time for a new hose.
By the way, always replace hoses in pairs if they are installed in pairs. For example, don’t replace just one front hose—the car will likely pull to one side because of differing amounts of compliance in each front line.
8. Check the Linkages
A lot of the brake pedal travel and feel is dictated by compliance in the system. After you’ve checked that all the components are not leaking and are in good shape, look for wear (and therefore compliance) in the pedal/master cylinder linkage and in the rear brake/parking brake linkages.
A small bit of wear in any of these can translate into an inch or more of pedal travel, plus a sloppy feeling. When you repair or reassemble these linkages, make sure to grease them appropriately for smooth operation.
9. Rotor and Drum Surfaces Do Matter
The surface finish on your rotors and drums is another important aspect to stopping power. Obviously, grooves are bad, but so is glazing. New parts or a trip to a shop that can put a good surface finish on your parts will help get you the stopping power you need.
10. Do You Really Need Those Big Brakes?
While most people seem to think a big brake kit is a great idea, it’s sometimes not necessary, especially if your car runs on the street. Many people jump to a big-brake kit before they even maximize their stock setup.
If you can lock up your wheels and tires, you don’t need bigger brakes—you need stickier tires. Once you’ve got the stickiest tire you can fit, then you can start thinking about bigger brakes.
Next, consider whether you can lock your brakes up when they’re cold, and how many stops it takes to induce fade. If you can induce fade, then you may want to experiment with different pads (or shoes) before jumping on the big-brake bandwagon. Remember, big brakes usually weigh more than the pieces they are replacing, and weight, especially rotating unsprung weight, is something we usually want to avoid.
Now We’re Stopping
Before you accuse your car of having badly designed brakes, make sure you’ve looked at the preceding areas. Your car should stop straight and within a reasonable distance. The pedal should move no more than a couple of inches. Don’t accept the “it’s an older car, what do you expect?” excuse for bad brakes—make sure they’re in good shape before considering upgrades.
