Product Summary

Universal Fit, Disc/Disc Brake System Type

  • Perfect solution to add power brakes to engines with large cams and low vacuum as well as boosted applications such as turbo or supercharged engines
  • 12 volt electric power booster unit can be remote mounted anywhere below the level of the master cylinder and will clean up the firewall appearance on your car
  • Master cylinder size is small enough that it can be located on the firewall, under the dash, or under the floor which provides you with a variety of options for installation
  • 1 3/16” bore master cylinder is for use with disc front and rear brake systems and is compatible with nearly any brake caliper from stock to aftermarket including 4 piston and 6 piston calipers
  • Kit includes master cylinder, 12 volt booster unit, proportioning valve, residual valves, brake lines, and fittings

Comes as a Kit

Key Specs

MFG. Part #9109938
BrandSpeedway Motors
Brake System TypeDisc/Disc
Master Cylinder MaterialAluminum

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Speedway Motors 9109938 Details

  • 12-volt electric power brake booster can be mounted almost anywhere
  • System provides up to 2,000 psi of brake line fluid pressure to brakes
  • 1-3/16-inch bore master cylinder designed for use with disc/disc braking system
  • Master cylinder is compact enough to use directly on firewall, under dash, or under floor
  • Perfect solution for engines with low vacuum signals, diesel engines, and boosted applications
  • Eliminates unsightly and bulky vacuum power brake booster from firewall
  • Hydraulic accumulator stores up to 15 full assist brake applications once 12-volt power removed
  • Polished aluminum master cylinder and cap looks great under hood
  • Electric power brake booster is very quiet and includes rubber isolators for mounting
  • Master cylinder fluid ports are standard 3/8-24 inverted female flare; no special adapters needed
  • Includes 4 feet of 3/8-inch fluid supply hose to plumb master cylinder to electric brake booster
  • Complete kit includes proportioning valve, brake lines, fittings, and residual pressure valves
  • Compatible with all DOT3, DOT4, and DOT5 brake fluid types

Modern Power Brakes Without Relying on a Vacuum Signal

As much as we all love to drive our hot rods, muscle cars, and classic trucks, there are a few safety aspects that we feel require improvement to handle the demands of today’s traffic, road speeds, and distracted drivers. We want to enjoy our rides and make it to our destination safely, and to do so improvements in lighting, braking, steering, and visibility are tops on our list. Updating your vehicle’s lighting is rather simple, as is making it more visible to other drivers. Steering and braking are a bit more involved, but far from impossible either.

One of the easiest ways to add power brakes to your ride is with one of our compact electric power brake booster and master cylinder kits. Installation is greatly simplified over the traditional large diameter brake vacuum booster that takes up valuable engine bay and firewall real estate. Furthermore, you do not have to worry about your performance modified engine with its aggressive camshaft and not having enough vacuum signal to allow the vacuum brake booster to work properly for power brakes. Installation is simple and the compact components fit almost anywhere, allowing just about any hot rod, classic truck, or muscle car to be equipped with much safer electric power brakes for modern driving safety.

Built with Solid Components Designed to Last

Our compact electric power brake booster and master cylinder combo kit is designed with premium components that will last the life of your ride. The dual port safety-style master cylinder is crafted from aluminum and receives a high polish finish to compliment whatever you have going on under hood. The master cylinder’s 1-3/16-inch bore size easily handles your disc/disc application, including modern multi-piston disc brake calipers. The brake master cylinder mounting ears are slotted, providing a center-to-center mounting distance variance from 3-1/16-inch to 3-7/16-inch, covering most any master cylinder mounting pattern. The brake master cylinder also features an adjustable brake pedal pushrod that is threaded to allow the perfect pedal positioning under your dash. All brake system fluid ports on the master cylinder are industry standard 3/8-24 inverted female flare that take standard 3/16-inch brake lines. No adapters or conversion fittings necessary, providing a cleaner installation and fewer potential leak points.

The 12-volt electric power brake booster is the other half of this dynamic duo and creates an astonishing 2,000 psi of brake fluid line pressure at maximum output to ably handle any braking system. The electric brake booster has a compact footprint that allows it to be mounted just about anywhere (so long as it is lower than the master cylinder) and includes a mounting bracket with rubber isolators for quiet operation. The electric brake booster features an accumulator that stores the pressurized brake fluid, allowing you to safely apply the brakes up to 15 times after power is removed from the unit. This is much greater than the two to three applications a vacuum brake booster provides once the engine is shut off. An integral pressure switch keeps the unit primed and ready for braking action and all wiring with relay is included.

In addition to the electric power brake booster and brake master cylinder, we include the correct residual pressure valves, adjustable brake proportioning valve, master cylinder hard lines, and all the brake lines and fittings you need to completely plumb your disc/disc brake system on your hot rod, muscle car, or classic truck in this kit. Other than ordering your favorite brand of brake fluid and determining the correct flex hoses for your front calipers (if they did not already come with new hoses) this is everything you need for your brake system’s fluid path from the master cylinder to the four corners of your ride.

Installation is a Breeze on Any Vehicle

The compact size of the remote brake booster unit means you can mount it just about anywhere. Measuring just under 7 inches long with a 6-1/4-inch height and 4-1/4-inch width, it will neatly find a home from the engine compartment inner fender area to the frame rails of your vehicle, even all the way in the trunk. All you must do is maintain a mounting location lower than the master cylinder (the pump’s inlet works off gravity from the fluid source in the master cylinder) and provide a high-pressure brake line from the electric brake booster pump unit back to the master cylinder to provide the pressure to the brake components. This line can be a length of hard line from the kit plumbed between the two, or you can install an inverted flare to AN 3 brake line fitting in the booster outlet and master cylinder inlet ports and use a length of stainless braided AN 3 brake hose for easier routing for remote installation locations for the brake booster unit. Wiring is a simple matter of connecting the heavy red wire to your battery and the tan wire to a switched 12-volt source (either directly from the ignition switch or an auxiliary ignition switched spot in your fuse box).

The brake master cylinder unit measures in at 9-1/4 inches long, allowing it to mount in most any location, including compact muscle cars with shock towers where a standard dual reservoir master cylinder and vacuum brake booster combination may not fit. Width and height of the brake master cylinder is quite compact as well at 3-3/8 inches and 4-1/8 inches, respectively. Mounting to your firewall or frame crossmember is made easy with slotted mounting ears that allow the brake master cylinder to be mounted to most any two-bolt pattern without modification. The threaded master cylinder pushrod is adjustable from 5-3/4 inch to 6-3/8 inch in total length and includes a standard brake pedal pin eyelet end fitting. We offer a generous line of brake master cylinder pushrod extensions, adapters, and clevis ends to adapt to just about any pedal assembly as well. All fluid ports on the master cylinder are standard 3/8-24 inverted flare that use 3/16-inch brake line.

Kit Contents:

  • (1) Compact Electric Brake Power Booster Master Cylinder, Disc/Disc
  • (1) Speedway Black Adjustable Brake Proportioning Valve
  • (1) Speedway Disc Brake Residual Valve, 2 PSI, Polished
  • (1) Speedway Drum Brake Residual Valve, 10 PSI, Polished
  • (1) Dual Outlet Master Cylinder Steel Dual Brake Line Kit
  • (1) Speedway 3/16-inch Steel Brake Line, 25 Ft. Roll
  • (1) Set of 5 Inverted Flare Thread Nuts for 3/16-inch Tubing, 3/8-24
  • (1) 3/8-24 IFF Each End, 1/8-inch NPT Female Center, Brass Adapter Tee
  • (2) IFF Brass Union Couplers, 3/8-24 IFF to 3/8-24
  • (2) 90 Degree 3/8-24 IFF to 1/8-inch NPT Male Adapter Fittings
  • (4) Straight 3/8-24 IFF to 1/8-inch NPT Male Adapters

Speedway Black Adjustable Brake Proportioning Valve

  • Allows easy adjustment of front to rear brake bias
  • Universal design works on all race cars. 100 to 1,500 psi range, up to 57 percentpressure reduction
  • Uses 1/8-inch NPT fittings
  • Compensates for weight transfer to the front wheels during braking
  • All factory brake systems allow for this in some fashion
  • An APV allows you to "fine tune" a street or race brake system (which normally uses components from a variety of sources) and thus prevents severe rear brake lockup under moderate-to-heavy braking

910-31355 Instructions (pdf)

Speedway Brake Residual Valves, Polished

Ever had problems with a spongy pedal or slow, unresponsive brakes? If so, you may need a residual pressure valve installed in your brake line. A redesidual valve acts like a one-way or check valve to maintain brake system pressure to eliminate the problems of a spongy pedal.  Installing these valves ensures that you will have a high, firm pedal next time you press the brake pedal.

Our residual pressure valves features a fully polished finish with a 1/8-inch NPT port at each end.

     2 PSI Disc Brake Valve

  • Included 2 PSI residual valve is installed inline between the master cylinder and disc brake calipers to keep 2 PSI of residual pressure at the caliper after the brake pedal is released.
  • If your master cylinder is located below the floorboard, installing a 2 PSI residual valve is highly recommended. If your master cylinder is mounted on the firewall, a residual valve is generally not needed because gravity will provide a natural residual pressure within the brake line.
  • Use 2 PSI residual valves for disc brake applications only.

     10 PSI Drum Brake Valve

  • Included 10 PSI residual valve is installed inline between the master cylinder and drum brake wheel cylinders to keep 10 PSI of residual pressure at the wheel cylinder after the brake pedal is released.
  • Use 10 PSI residual valves for drum brake applications only

Dual Outlet Master Cylinder Steel Dual Brake Line Kit

  • Intended to simplify plumbing from the master cylinder to a proportioning block
  • Features tight 90° bends at the master cylinder end
  • Both ends of both lines are 3/8-24 inverted flare nuts
  • The longer of the two lines measures approximately 12 inches from the bend to the end

Speedway 3/16-inch Steel Brake Line, 25 Ft. Roll

  • Zinc coated steel brake linefor added strength and durability
  • Available in a 25-foot roll of 3/16-inch line
  • Bends easily and smoothly with hand tools and can be flared with a 45° double flaring tool
  • Use in conjunction with the included 3/8-24 inverted flare male brake line nuts


Speedway Motors 9109938 Specifications

MFG. Part #9109938
BrandSpeedway Motors
Brake System TypeDisc/Disc
Master Cylinder MaterialAluminum
Brake Booster TypeElectric
Outlet CountTandem
Outlet Fitting3/8"-24 IFF
Master Cylinder Bore Size1-3/16 Inch
Mounted Length9.25"
Master Cylinder Port Sizes3/8"-24 IFF
Master Cylinder Built-In Residual ValvesNo
Master Cylinder Cap IncludedYes
Mounting Bracket IncludedYes
Centerline of Holes3.33"
Proportioning Valve IncludedYes
Proportioning Valve MaterialAluminum
Proportioning Valve LocationUniversal Mount
Brake Pedal Rod IncludedYes
Reservoir IncludedYes
Reservoir MaterialAluminum
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