Menu

Shop

Garage

Cart

Account

Product Summary

Universal Fit, 7 Inch Brake Booster Diameter

  • Compact design adds vacuum assist for increased brake pedal response, easily mounted under the hood or floor of most vehicles
  • NEW heavy duty steel booster measures 7" in diameter and has a zinc plated finish for corrosion resistance
  • Master cylinder has a 1" bore with 3/8"-24 IFF outlets on both sides of the M/C allowing for brake lines to be run specific for your needs
  • Mounting for the booster has 3-3/8" on center, 4 bolt pattern to simplify installation
  • Mounted overall length is 11.75"

Comes as a Kit

See more details

Key Specs

MFG. Part #91031409
BrandSpeedway Motors
Brake Booster Diameter7 Inch
Master Cylinder MaterialSteel
See more specs

Need To Know

Quick and Easy Returns

Return Policy

Speedway Motors 91031409 Details

Compact for installation under floor or on firewall of almost any vehicle. Booster measures only 7" in diameter. Cast iron master cylinder has a 1" bore and is suited for disc-disc or disc-drum combinations.

Master cylinder features two 3/8"-24 inverted flare ports on each side (plugs are included for ports not in use).

  • Compact design to fit into small spaces under the hood
  • Universal in design, makes for a simple install
  • Heavy-duty zinc-plated steel construction to provide years of service
  • Uses standard DOT 3 or DOT 4 brake fluids

Learn more about selecting the proper master cylinder for your vehicle by reading our tech article. Brake System Selection.

Specs

  • Pushrod-to-mounting flange is 5-1/2"
  • Four bolts on 3-3/8" centers
  • Booster is 3.75" thick
  • Master cylinder combo is 11.875" from end of the master cylinder to the firewall
  • (4) qty 3/8"-24 outlet ports (2 plugs included)
  • 8" from mount to outer edge

Speedway Motors 91031409 Specifications

KEY SPECS
MFG. Part #91031409
BrandSpeedway Motors
Brake Booster Diameter7 Inch
Master Cylinder MaterialSteel
GENERAL
Brake Booster TypeVacuum Diaphragm Single
Outlet CountTandem/Both Sides
Outlet Fitting3/8"-24
Master Cylinder Bore Size1 Inch
Brake Booster MaterialSteel
Overall Length11.75"
Master Cylinder Port Sizes3/8"-24 IFF
Bolt Hole Pattern3.38" x 3.38"
Centerline of Holes3.38"
Reservoir IncludedYes
Sold in QuantityKit

Ratings & Reviews

4.8

51 Reviews

Overall Assessment

Customers highly recommend our product for its excellent quality, ease of installation, and compact design. They found it to be a great upgrade and a fit for various car models like the '56 Dodge, '49 Chev, and '37 Chevy coupe. Specific comments highlight the product's high performance, great braking improvement, and perfect fit in small areas. However, users note needing clear instructions for better usability. It's also praised for requiring minimal modifications, making it practical for those restoring older models. Repeated purchases reflect customer satisfaction and faith in the product's efficiency and top-notch material quality. A few highlighted the product's safety, stating the improved brake systems. The product stood out in its category, with many choosing it over competitors.

4.8

51 reviews

5

44

4

5

3

1

2

0

1

1

Most Liked Positive Review

5.0

Master Cylinder & Booster

Bought to replace leaking system under the floor of my Model A. It was a direct bolt-in, all fittings and mounts were lined up and only had to fab a new pedal to booster connection. Very straight forward install, and now have plenty of brake (disk/drum). Now the car stops as well as it goes, has been a bit of a problem in the past. Should have replaced the system a couple of years ago.

Most Liked Negative Review

3.0

Booster and Master Cylinder

Lack of ANY INSTRUCTIONS resulted in me having to call the tech line TWICE!!! Even the calls did not resolve all of my issues with these units. There also should be a simple bracket to mount the booster to the firewall. I bench bled the Master cylinder, vacuum bled each wheel twice and still could not achieve a normal pedal height. Adjusted pedal push rod and booster push rod and still very low pedal.

Filter by Ratings

I have good power brakes again

5.0

a month ago

Kevin Hotrod

Queen Creek, AZ

Verified

I purchased this for my 36 Ford Hotrod. about 20+ years ago when I got the car and new to hotrodding, the master cylinder went out. I took it to my Oreillys to match it up. I was paying more attention to the port size and location and overall appearance. I did not know anything about bore sizing. Drove it for 20 yrs with a high, HARD pedal. So, replaced everything under the floor and man, what a difference. Stops with toe pressure rather than leg pressure.

Would Recommend

Product is very flexible and effective

5.0

6 months ago

Mike honcho

Dewees texas

Verified

The product went on my 1971 wagoneer and didn't seem like it would go on original brackets. Managed to get it on anyways and was able to buy some pushrod extension parts to get it to the pedal

Would Recommend

Brake system

5.0

11 months ago

The 40

Palmdale CA

Verified

Goes in a 40s frame with cross member and fits great

Would Recommend

yes

5.0

a year ago

bob

Mora, MN 55051

won't use until spring

Would Recommend

Would buy again

4.0

a year ago

51

Toledo, WA

Verified

Updated my brakes to front discs, exactly what I needed. Thank you

Would Recommend

I would buy this booster, master cylinder combo again.

5.0

a year ago

Dan

Northern e

Verified

I used it to replace an old 77 Camaro set up that was leaking on my 1950 Pontiac custom hot rod. It gave me more room on the fire wall and in the engine bay. It

Would Recommend

Very good quality booster and master cylinder

5.0

a year ago

Birdman

Iowa

Verified

It's advertised as universal, but I was unable to drill holes in the firewall to mount it. There's a bracket on the rear side of the firewall that was in the way. This is on my 1971 mustang. I have returned it to speedway motors. I should have measured before ordering it f

Would Recommend

If needed, I wouldn't hesitate to buy another.

5.0

a year ago

Bob

Ohio

Verified

Product worked as expected, quality was good.

Would Recommend

good product great price

5.0

2 years ago

MR. NOBODY

FL

Verified

GOOD FIT ALONG THE FRAME RAIL.

Would Recommend

Just what we were looking for

5.0

2 years ago

JJ

Cottonwood mn

Verified

Working great for my Grandsons 1956 rebuild on a Dodge frame

Would Recommend

Load More Reviews

Showing 10 of 51 reviews

Customer Impersonation Script