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What Are Electric Powered Brakes?
Electric powered brakes are a modern alternative to traditional vacuum-powered brakes commonly found in vehicles. While vacuum-powered brakes rely on engine vacuum to assist with brake pedal effort, electric brakes utilize an electric pump and booster system to provide the necessary braking force. These systems are particularly useful for vehicles with low engine vacuum, aggressive camshafts, or forced induction setups such as superchargers or turbochargers.
One popular electric brake system is the JEGS Electric High Power Brake System. This system features a polished aluminum finish and offers easy installation and superior performance. The electric booster system can be mounted almost anywhere and eliminates the need for engine vacuum. It is an excellent choice for various vehicles, including street rods, classics, muscle cars, and hot rods.
How Do Power Brake Boosters Work?
Power brake boosters play a crucial role in assisting brake pedal effort, making braking more efficient and responsive. In traditional vacuum-powered systems, the brake booster uses engine vacuum to create a pressure differential that amplifies the force applied to the brake pedal. However, in electric brake systems, the power brake booster operates differently.
The JEGS 631250 Electric Brake Booster and Master Cylinder Combo is designed to deliver exceptional braking performance in vehicles with low engine vacuum. It features a compact and versatile booster design that allows for mounting in various locations. The system incorporates an integral relay and pressure switch, which are pre-wired, requiring only a ground connection, a 12-volt battery connection, and a keyed ignition connection.
The whisper-quiet power booster unit draws only 14 amps at maximum pressure, ensuring efficient power delivery while remaining quieter than most performance electric fuel pumps. This system incorporates a hydraulic accumulator ball that acts as a capacitor in an electrical circuit. The accumulator ball stores pressure, resulting in smooth brake actuation and providing additional reserve pressure in case of a failure in the vehicle's electrical system. This built-in safety reserve allows for 10-15 full-assist stops before the pedal gradually firms up as the pressure in the boost circuit decreases. In the event of zero pressure in the booster circuit, manual brakes become available.
Converting Your Brakes Yourself
Converting your brakes from vacuum to electric can be a rewarding DIY project. Here are some steps to guide you through the process using the JEGS Universal Electric Brake Booster and Master Cylinder Combo:
Mounting the System
- Install the Master Cylinder: Mount the master cylinder to the firewall and connect the push rod to the brake pedal.
- Install the Electric Brake Booster: Install the electric brake booster, ensuring that it is mounted away from heat sources. It is critical to mount the booster lower than the master cylinder to facilitate proper fluid return flow.
- Make Brake Lines: Create brake lines specific to your application. Connect all lines to the appropriate ports. The master cylinder ports are 3/8 in.-24, designed for use with standard SAE 3/16 in. brake lines. Refer to the illustration provided by the manufacturer for the correct port locations. (Note: The return line and clamps are included with the system.)
- Connect Wiring: Connect the large red wire to a 12-volt battery source. Connect the tan wire to a keyed ignition source. Connect the black wire to ground.
- Thoroughly Inspect Connections: Once all connections have been made, thoroughly inspect each connection for security and proper wiring.
- Bleed the System: Bleed the brake system following the instructions below.
Bleeding the System
For the initial bleeding process, you will need two people—one to operate the brake pedal and the other at the bleeder on the wheel cylinder or caliper. Follow these steps:
- Fill the Master Cylinder: Remove the cap of the master cylinder and fill it with brake fluid, ensuring the fluid level is 1/4" from the top. Begin by bleeding the front brakes and then move to the rear brakes. Confirm that clear fluid, free of bubbles, is coming out of each bleeder. Refill the brake fluid reservoir, maintaining the level no more than 1/4" from the top. Avoid allowing the reservoir to become empty, as it would require restarting the bleeding process.
- Bleed the Pressure Valve: Attach a clear hose to the bleeder fitting on the pump pressure port to contain any excess fluid during bleeding. Loosen the pressure line bleeder and turn the ignition switch to the "on" position. Allow the pump to run until you see a continuous stream of fluid. Then, tighten the fitting and turn the ignition switch to the "off" position.
- Remove Excess Fluid and Achieve Full Pressure: Remove any excess fluid and turn the ignition on. Let the pump run until full pressure is achieved, and the pump turns itself off.
- Finalize the Bleeding Process: The system is now fully pressurized and ready. With the ignition on, apply pressure to the brake pedal and thoroughly check the entire system for any signs of leaks before test driving the vehicle.
Note: The fluid level in the master cylinder should be 1/4" from the top. Do not overfill the reservoir.
Remember to follow the manufacturer's instructions carefully throughout the conversion process. Following these steps and bleeding the system properly will ensure the safe and reliable operation of your newly converted electric brake system.
Converting from vacuum to electric brakes offers improved braking performance for vehicles with low engine vacuum or special engine configurations. Electric brake systems, such as the JEGS Electric High Power Brake System, provide easy installation, enhanced braking power, and versatile mounting options. With careful planning and the right tools, you can successfully convert your brakes to electric and enjoy the benefits of modern braking technology.
17 responses to “Converting from Vacuum to Electric Brakes”
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i am mounting a electric power brake system in a 1952 flat head Merc pickup the relay was removed , so i installed the relay in the engine bay, i would like a diagram as to how i should reconnect the relay
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Don, the wiring for an electric power brake booster relay is fairly straightforward, but the exact connections depend on the brand and style of system you are using. Most electric brake assist units from companies like ABS Power Brake or Leed Brakes use a standard four or five pin automotive relay to control power to the electric pump motor. In a typical setup, the relay terminal that receives battery power is connected directly to a fused 12 volt source from the battery. The terminal that sends power out of the relay goes to the electric brake pump motor. Another terminal is connected to a switched ignition source so the system only operates when the key is on. The remaining terminal is the ground that completes the relay control circuit. When the ignition is turned on and the pressure switch in the brake system calls for pressure, the relay energizes and supplies full battery voltage to the pump motor. Since your relay was removed and you are reinstalling it, the challenge is that different systems may place those connections on different numbered terminals, and some systems also include a pressure switch in the trigger circuit. Without knowing the exact brand of the electric brake unit or the style of relay that came with it, it would not be accurate to give a specific pin by pin wiring diagram. If you can identify the manufacturer of the electric brake system or the relay configuration, we can narrow it down much more precisely. Ideally we would like to help walking through the wiring with your setup, give us a call at 1-800-345-4545 and speak with a Tech Specialist and we will be glad to help.
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Tremblay, if you converted from vacuum assist to an electric brake booster system, it is actually normal for the system not to hold assist pressure for hours after the vehicle is shut off. Most electric assist units build pressure when powered on and may cycle to maintain it while the key is on, but once the vehicle sits with the ignition off, the stored assist pressure can bleed down internally over time. That does not automatically mean you have a leak, especially if everything is dry and you are not losing brake fluid. A hard pedal after the vehicle has been sitting usually just means there is no assist available until the electric pump runs again. When you turn the key back on, you should hear the pump cycle and the pedal should regain assist feel. If the pedal remains hard even with the system powered and the pump running, then that would point to a problem with the booster, pressure switch, wiring, or power supply. Systems from brands like Leed Brakes are designed to cycle as needed and do not necessarily maintain full stored pressure for long periods with the vehicle off. As long as there are no fluid leaks and assist returns when powered up, what you are describing can be normal behavior. If you would like to go over your exact setup in more detail, give us a call at 1-800-345-4545 and speak with a Tech Specialist and we will be glad to help.
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Is it normal that my system doesn’t maintain its pressure after 2 to 3 hours without operation? thanks
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Is there a remote reservoir for this system that would allow the master cylinder to be mounted verticle?
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Larry, the electric brake booster itself does not use or require a remote reservoir, since fluid storage is handled entirely by the master cylinder. Whether you can run a remote reservoir and mount the master cylinder vertically comes down to the master cylinder design, not the electric booster. Many aftermarket master cylinders that are compatible with electric boosters can be run with a remote reservoir as long as they are specifically designed for that setup and have sealed ports for remote hoses. If the master cylinder is designed for vertical mounting and remote reservoirs, it will work fine with an electric booster, but a standard top fill master that relies on gravity will not behave correctly once turned vertical. This is one of those cases where the booster is flexible but the master cylinder choice is critical, so confirming the master cylinder style, bore size, and reservoir configuration is key before committing to the layout. If you want to talk through master cylinder options that are known to work with electric boosters and remote reservoirs, our tech team can help you dial that in and avoid brake feel or bleeding issues. You can call 1-800-345-4545 and speak with a tech specialist to handle any additional questions you might have.
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Another question.
The only place I have to mount the booster would be in the front drivers wheel well. Can it get wet? I would probably fab some kind of shield for protection, but does it. have to be water tight?I wonder how this stacks up to the Bosch iBooster from a Tesla/Honda etc. I know the iBooster is much less expensive.
Thank you!
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Mounting an electric brake booster in the front wheel well is possible, but it does require some care. These electric boosters are not designed to be submerged or directly exposed to road spray. Occasional moisture from normal driving is usually not an issue, but constant water, mud, or direct splash can shorten the life of the motor, pressure switch, and electrical connections. Fabricating a solid splash shield is strongly recommended. The goal is to keep direct water spray, debris, and road grime off the unit while still allowing some airflow so heat can escape. It does not need to be completely sealed, but it should be well protected and mounted securely with the wiring routed and sealed properly.
As for comparing it to a Bosch iBooster from a Tesla, Honda, or similar vehicle, there are some important differences. The iBooster itself is a very capable unit, but it was designed to work as part of a modern OEM braking system. It relies on CAN communication, vehicle speed inputs, brake pressure sensors, and an ECU to function correctly. Without the factory electronics and software, it becomes very complex to integrate into a classic or custom vehicle. That added complexity is why it often ends up costing more in time and supporting parts, even if the booster itself looks inexpensive at first. Purpose built aftermarket electric boosters are designed to operate as a standalone system with simple wiring and no computer integration, which makes them far more practical for retrofits.
If you want to go over mounting options or talk through whether an electric booster is the best fit for your layout, give us a call at 1-800-345-4545 and one of our tech specialists will be happy to help you sort out the details.
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Can the Electric Power Booster be used with an existing master cylinder with a remote reservoir and can it be mounted a foot or so from the master cylinder?
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Paul, in most cases an electric power brake booster is designed to work with a specific style and bore size master cylinder, and many systems are intended to be used as a matched booster and master assembly to ensure proper pressure, pedal feel, and safety. Using an existing master cylinder with a remote reservoir can work, but only if the master cylinder bore size and internal valving are compatible with the electric booster’s pressure output and flow requirements. The remote reservoir itself is usually not an issue as long as it feeds the master correctly and stays higher than the master cylinder to prevent air intrusion. As for mounting distance, electric hydraulic boosters can typically be mounted remotely, including a foot or more away from the master cylinder, as long as the high pressure brake lines between the booster and master are rated for the required pressure and properly secured. Line routing and fittings become very important here, since electric boosters operate at much higher pressures than vacuum systems. Because compatibility varies by booster design and master cylinder type, this is one of those setups where confirming bore size, brake configuration, and line routing is critical before buying parts. For help making sure everything works together safely, give us a call at 1-800-345-4545 and speak with a tech specialist who can walk through your exact setup and steer you in the right direction.
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For the JEGS electric brake booster setup, you want to be right in the same range as a traditional power brake pedal. A ratio around 4 to 1 or 4.5 to 1 works well with this system. That ratio keeps the pedal effort comfortable while still giving the booster the leverage it needs to build proper line pressure. A manual brake ratio like 6 to 1 is too high for an electric booster and will usually make the pedal feel touchy or overly sensitive. If your vehicle currently has a manual pedal, you would want to move the pushrod pin location to the power brake hole on the pedal arm, or adjust the pedal geometry so it falls into the 4 to 1 range. If you want someone to walk through your exact setup and confirm the ratio you have now, give our tech team a call at 1-800-345-4545 and they can go over it with you.
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Henry,
Please go to http://www.jegs.com, add it to the cart and proceed to checkout. Once your address is put in the shipping information, it will show you the total price to ship to the Netherlands.
Thank you for your interest!!-
Can you use this braking system to tow a vehicle and have it electrically apply the brakes to the tow vehicle?
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Hi Rodney, that’s a really good question. The JEGS Electric Brake Booster and Master Cylinder Combo you’re looking at is designed strictly as a replacement for vacuum-assisted brakes on a vehicle. Its purpose is to generate brake line pressure for the vehicle it’s installed on, especially in builds where there’s low or no engine vacuum, like with big camshafts, turbos, or superchargers.
It’s not designed to act like a supplemental braking system for a vehicle you’re towing. Tow brake systems work differently and are specifically engineered to sync with the towing vehicle, applying braking force to the towed vehicle in proportion to what the driver is doing. The JEGS electric booster can’t safely replace or function as that kind of setup.
If your goal is to tow a vehicle and have it brake electrically, you’d need a dedicated trailer brake controller system paired with electric or electric-over-hydraulic trailer brakes. That ensures proper proportioning, safety compliance, and reliability during towing.
If you’d like, our tech support team can walk you through options for proper towing brake systems and help make sure you’re set up safely. You can reach them at 1-800-345-4545 for more detailed guidance.
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