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Brake Boost

More stopping power by tapping into your power steering system

To achieve big power, it's basically a given that high-performance cars run a radical camshaft. Trouble is, many hot rodders think more about the go rather than the slow. So when they're ramming around town with a performance grind on your bumpstick, they may encounter a problem with stopping if their rod relies on a factory-style, vacuum-powered brake assist unit. This system can present a substantial problem with braking at low engine rpm, due to an inadequate vacuum supply to the brake booster because of the cam's extreme lobe shape. On top of that, other areas of the car, such as automatic transmissions and A/C systems, also need vacuum, which then takes it away from the brake system.

Hydroboost

A quick remedy for this scenario is to use a product that has been commonly available as a general automotive service part since 1974. This proven approach is currently found on a wide range of new production vehicles, everything from V8 Mustangs to Chevy pickups. As such, it has undergone rigorous testing by OE manufacturers to insure proper operations and reliable operation.

Called a hydroboost, this hydraulic brake assist relies on hydraulic pressure from the power steering pump to provide far more brake assist power. For comparison, a standard vacuum unit normally can produce only 450 psi, while a hydroboost system can generate anywhere from 1200 to 2000 psi to the calipers.

If your vehicle already has a master cylinder (assuming it has power steering to begin with, which is required to add a hydroboost system), in most cases it can be used, as long as it is in proper operating condition. If your master cylinder is more than 10 years old, though, or shows signs of aging and wear, it should be replaced.

A number of companies offer hydroboost systems for a wide range of cars and trucks, not just hot rods and muscle cars. For customized rods in particular, a clean-looking engine bay is especially important. For this type of application, hydroboost from Power Brake Service is handcrafted to a high level of visual quality. The units can be anodized or finished with a chemical-resistant paint. The line sets use Aeroquip TFE spec materials, with adjustable aluminum line separators featured in most applications.

System Setup

Included with a hydroboost system is an accumulator or nitrogen reserve. It stores up hydraulic power steering pressure in the event of an engine-stall condition in order to provide reserve brake assist power for up to three full-power applications of the brake (similar to how a vacuum booster functions in an engine-stall condition). Once you have depleted all of the stored pressure, the brakes will no longer have power assist and will be manual in their operations. The minute you start the vehicle back up again, the accumulator gets filled back up again with pressurized hydraulic fluid.

If spacing is an issue in the engine bay, as is common with many older body styles, the hydroboost saves room over a typical vacuum brake booster, usually about four inches more spacing for tall valve covers, in comparison to the average vacuum brake booster. Of course, the space savings will vary from vehicle to vehicle, and if necessary, the unit can be mounted remotely in the chassis, as shown in the photos.

Some really older vehicles may have drum brakes up front, which is not recommended for a hydroboost system. In this case, you'll also need to add a front disc brake conversion kit, available from a number of aftermarket companies. Whatever your vehicle type, if you're going to swap out the cam for more engine power, consider boosting the brakes at the same time, to make sure your ride has enough stopping power as well.

Resource

Power Brake Service, 562/983-1060, www.powerbrakesonline.com