Many enthusiasts spend plenty of time setting-up their Chevy to haul the mail. But, what about addressing the ability to hustle down their 3,000-pound ride? In many cases, the requirements necessary to build an engine that produces more torque and horsepower than the factory’s original offering could also reduce the vacuum the engine generates. To achieve more power, the camshaft likely has a greater advertised lift and vacuum-killing valve overlap than the factory unit. Depending on the engine, this bumpstick boogie means the brake vacuum-booster may not operate effectively, which will result in a hard pedal and increased driver effort to stop the vehicle.
Another situation that can lead to a problem is the substantial bulk of a vacuum booster. Regardless of the booster’s design (7-, 8-, or 9-inch dual-diaphragm or a single 9- or 11-inch diaphragm), the vacuum booster can take-up a great deal of underhood real estate. If a physically larger-than-stock engine is stuffed into the engine bay, the vacuum booster may interfere with the engine installation.
Lastly, if the engine swap is from a gasoline to a diesel engine, the vacuum booster will be ineffective due to the low vacuum generated by the diesel. In all three cases, there must be something that will work with whatever engine is installed in the engine bay, yet provide the driver with reliable braking assistance to stop their vehicle.
To alleviate these problems, Classic Performance Products (CPP) has developed the HydraStop system. The HydraStop unit is a high-quality, bolt-in, hydraulic-brake-assist system designed to upgrade manual- or vacuum-assisted brakes.
Hydraulic Brake Assist
What are hydraulic-assisted brakes? The origins of hydraulic boosters can be traced back to the late-1960s. Manufacturers realized government-proposed regulations on stopping distances and driver pedal effort were looming in the near future. Either a substantial upgrade to the existing vacuum-boosted braking systems was required, or a new system needed to be developed to meet the requirements.
In addition to the stricter braking obligations, the 1970s saw an increased development of hydraulic boosters as a result of the crude emission control devices of the era. In an attempt to reduce vehicle emissions — before the introduction of the catalytic converter — manufacturers retarded the engine’s ignition timing, and the design of the camshafts greatly increased the amount of valve overlap. Both resulted in reduced engine-vacuum production. This led to marginally effective vacuum boosters. The hydraulic boosters were compact units that could produce greater assist than a vacuum booster.
As braking systems evolved from four-wheel drums to discs, it was determined the increased assist of a hydraulic booster worked well with a front disc/rear drum setup, and it was a perfect match with four-wheel disc-brake systems. The hydraulic pressure was provided by an increased-capacity steering pump (although the steering box remained unchanged).
The All-In-One System
The CPP HydraStop system offers a suspended brake pedal, firewall-mounted design. For older vehicles, street rods, and specialty vehicles, CPP also offers a floor-mounted design. CPP covers a range of Chevrolet vehicles from the 1940s to the 1980s, and the HydraStop boosters can be ordered in one of three packages.
The first is the Show Stopper package, which includes the hydraulic brake assist unit with a billet-aluminum firewall mounting bracket, chrome master cylinder with a chrome, adjustable-proportioning valve distribution block, a chrome accumulator cover, stainless pressure hoses, rubber return hoses, and all necessary fittings and hardware for the installation.
The second is the Street Beast package that includes a hydraulic brake assist unit with a steel firewall mounting bracket, an aluminum Corvette-style master cylinder, a side-mounted proportioning block kit, and rubber pressure and return hoses. To install the HydraStop system, all the required fittings and hardware are included.
Lastly, the bare hydraulic brake assist unit can be ordered as a bare entity. All the HydraStop units use all new parts. Regardless of the system selected, a weekend warrior with average mechanical skills can complete the installation in a day with the use of nothing more than common hand tools.
CPP Engineer Danny Nix stated, “there are only three fluid lines routed to the hydraulic-assist booster to connect. The line connected near the accumulator supplies pressure from the pump to the booster. A second line supplies pressure from the booster to the steering gear. And a third, small line is a return line back to the pump reservoir.”
Higher Brake-Application Pressure
Compared to manual- or vacuum-assisted brakes, the hydraulic-assist systems provide the greatest pressure. It can exceed 1,800 psi, but does not require any additional driver effort to stop the vehicle. “Since the booster is so powerful, CPP recommends an upsized master cylinder bore. This helps create a better brake feel and less pedal travel,” Nix added.
The CPP HydraStop unit uses the pressure supplied by the power steering pump. As long as the pump pulley is spinning, you have braking power. “When the engine is stopped, the accumulator has a reserve of hydraulic pressure than can provide several safe stops. After the reserve is used, the brakes will operate as normal manual brakes. With the high-pressure brake assist available, you may consider using a less aggressive brake pad for longer service intervals,” Nix stated.
Advantages And Disadvantages
As previously described, there are many benefits to using the HydraStop system. The unit is compact, provides plenty of brake-assist pressure, and does not require engine vacuum. It has plenty of brake pedal application reserve, and it is a bolt-in system. Best of all, it can be installed by nearly anyone with a mechanical aptitude. With all the positives of the HydraStop, there must be some disadvantages when using a hydraulic-assist braking system.
The downfalls of the system are very few. In general, the HydraStop system is slightly heavier than a vacuum-assisted system and is certainly heavier than a manual system. This is a relatively small concern. Unless weight is critical, the benefits of the HydraStop system greatly overshadow this disadvantage. Another concern is the additional hydraulic plumbing and the opportunities for leaks. If the fittings of the hoses are properly tightened and the hoses are appropriately routed to not interfere with hot or rotating components, the leak concern is minimal.
When going from a manual- or a vacuum-assisted braking system to a hydraulic-assist system, the initial feeling may result in the user having some concerns. For instance, the hydraulic-assisted system may seem difficult to modulate and the brakes often feel “touchy.” This is only due to a lack of familiarity with the increased performance of the HydraStop system. After a few weeks of driving the vehicle, the driver will have a better feel for the braking system, and it will no longer be a concern.
CPP does have a few recommendations/requirements for the HydraStop system. CPP recommends a filter installation to capture the damaging contaminants and protect the internal seals and valves. Debris will shorten the life of the HydraStop unit, pump, and steering gear. If an old steering pump is used, it must be cleaned. It needs to flow at least two gallons of power steering fluid per minute. Any less, and delays in brake-assist may occur and reduced power-steering assist could result when the brakes are applied. A quality pump should achieve at least 1,200 psi.
When using an old master cylinder with the HydraStop, the increased pressure from the hydraulic assist will cause the master cylinder to develop much higher line pressure compared to a manual or vacuum-assisted system. “A worn master cylinder may develop internal or external leaks with these higher pressures,” affirmed Nix. Therefore, the use of a master cylinder in good condition is required.
If you are looking for a quality, dependable braking assistance for your Chevrolet, maybe a hydraulic-assist braking system is for you. A HydraStop system has a huge list of benefits, and there are zero substantial drawbacks to installing the system. With a HydraStop system, you can have that huge cam, big-block, or a diesel, and still have outstanding braking capabilities. If a HydraStop system looks like the answer to your braking concerns, give the Classic Performance Products a call or check out the Classic Performance Parts website for all the information about the HydraStop.