Menu

Shop

Garage

Cart

Account

Product Summary

Ford 9 Inch, Rear Position, 11.25 Inch Rotor Diameter

  • Disc brake stopping power for Ford 9 inch rearends at nearly the same cost as rebuilding/replacing drum brakes
  • Kits include two bolt-on caliper brackets, two 11 1/4" vented rotors, two GM metric emergency brake style calipers, brake pads and hardware
  • Rotors have a 2.780" center hole with both 5 on 4 1/2" and 5 on 4 3/4" bolt circles
  • Fits over an axle with maximum flange diameter of 6 1/4" O.D.
  • Fits "old" and "new" style big bearing (3.150" bearing O.D.) Ford housings and with axle offsets of a minimum 2-3/8" to 2-1/2"

Comes as a Kit

See more details

Key Specs

MFG. Part #91031921
PositionRear
Rotor Diameter11.25 Inch
Rotor TypeVented
Caliper PistonsOne
See more specs

Need To Know

Quick and Easy Returns

Return Policy

Speedway Motors 91031921 Details

As featured on Classic Truck’s Week to Wicked. Watch the transformation here!

Disc Brake Stopping Power at a Great Value

This economical disc brake kit for Ford 9 inch axles is simple to install and provides big stopping power, at a price nearly the same as replacing original drum brakes. That Ford rear end handles the power to make it go, but these binders clamp down when you say whoa! Today’s average family sedan can stop from 60 MPH in 120 feet, at nearly 1G of deceleration. You need the same stopping power. Your passengers, you and your car deserve the confidence of disc brakes and our kit delivers that confidence with exceptional value.

Superior to Drum Brakes

Aftermarket disc brakes are superior to original drums in many ways: more braking force, less brake fade, and easier service. Stopping power starts with our newly manufactured GM Metric D154 style single piston calipers, commonly found on 1978-88 GM G-Body and A-Body cars. Large 11-1/4” diameter, 1” thick vented rotors provide more stopping leverage than common 9” or 10” drum brakes. Brake pads are easier to change than drum shoes, and our brake kit includes a street-friendly organic compound for long rotor/pad life. Replacement pads are common sized, available from your local auto parts store. Looking for more aggressive stopping power? We carry race-grade D154 disc brake pads that drop in just as easily.

Fits Ford 9 Inch Housings

This disc brake kit fits Ford passenger car Ford 9 inch axle housings with “big bearing” ends (3.150” O.D. bearing, found on passenger cars from 1974-79). Included bracketry will adapt this kit to both “new style” and “old style” Ford 9 inch housing flanges with the 3/8” bearing retainer bolt holes. Bracket spacers are also included, allowing this kit to work with axle flange offsets of 2-3/8” or 2-1/2” common on Ford 9 inch passenger car rear ends. Axle flange offset is measured from the axle housing flange face (with bearing retainer removed) to the axle shaft flange face (side where the brake rotor/drum rides, including the thickness of the axle flange). 

Hardware and Instructions Included

Kit includes a detailed, step-by-step instruction sheet with images. The floating calipers include new Grade 5 slider bolts, with all remaining hardware of Grade 8 quality. Cast iron rotors feature a dual bolt pattern in 5x4.5” (Ford/Mopar/AMC) or 5x4.75” (Chevy/GM) to match your desired wheel hub pattern. Plus, this assembly will clear most 15” diameter wheels designed with disc brakes in mind. Note that there are no provisions for a parking brake, making this the perfect disc brake conversion kit for the budget-focused builder who prefers a basic upgrade kit.

  • Disc brake stopping power at nearly the same cost as rebuilding/replacing drum brakes
  • 11-1/4” diameter, 1” thick vented cast iron rotors dissipate heat faster than drum brakes
  • Serviceable design ensures good drivability and piece-of-mind when on the road
  • Street-friendly GM D154 style pads, replacements available nearly everywhere
  • GM “Metric” style single piston calipers with 7/16”-20 banjo-style inlets
  • Fits Ford “big bearing” 9 inch housings from passenger cars and 8 inch rear ends
  • Use with Ford 9 inch rear ends with 2-3/8” or 2-1/2” axle flange-to-housing offsets
  • Dual wheel bolt patterns covering all GM/Ford/Mopar (5x4.5” for 1/2” studs, 5x4.75” for 7/16” studs)
  • Use with 15” or larger disc brake-style wheels
  • Easy bolt-on installation w/ included instruction sheet
  • Includes heavy steel mounting brackets, Grade 8 hardware and nylock nuts (everything you need)

 

Included in this Kit:

(2) 11-1/4 Inch Rear Brake Rotor

(1) GM Metric Disc Brake to 9 Inch Ford Bracket Set

(1) Ford 9 Inch Brake Bolt Kit

(1) 1978-Up GM Metric Emergency Brake Caliper, LH, 5.45 Mount Bolts

(1) 1978-Up GM Metric Emergency Brake Caliper, RH, 5.45 Mount Bolts

(1) Instruction Sheet

Application

  • "Old-style" big bearing 9" Ford axle
  • "New-style" big bearing 9" Ford axle
  • Axle housings with minimum axle offsets of 2-3/8" to 2-1/2"

This kit will NOT work on pickup housings or the 50's 9" housings as they only have about 2" backspace. The exception would be the late 50's station wagon rear ends.

When using with a Currie Axle with an o/d register of 2.795", the rotor is included in this kit with an i/d register of 2.78" and therefore will need to be machined by increasing the hole diameter in the rotor to match the Currie axle spec of 2.795"

Check out our Tech Talk on the Toolbox for more tips on this brake kit.

Charts

Specs

The caliper piston pin needs to be aligned with the notch in the pad to avoid fitment issues.

 

Speedway Motors 91031921 Specifications

KEY SPECS
MFG. Part #91031921
BrandSpeedway Motors
PositionRear
Rotor Diameter11.25 Inch
Rotor TypeVented
Caliper PistonsOne
Caliper FinishNatural
ColorNatural
Parking Brake ProvisionYes
Minimum Recommended Wheel Diameter15 Inch
Rotor ShapeRound
Hardware IncludedYes
Front Rotor IncludedNo
Front Caliper IncludedNo
Rear Caliper IncludedYes
Front Spindles IncludedNo
Master Cylinder IncludedNo
Brake Booster IncludedNo
Ford Bearing End StyleBig Ford (Old/New) & Small Ford
Rear Rotor IncludedYes
Bolt Pattern5 on 4.5" | 4.75"
GENERAL
Sold in QuantityKit
NotesWorks with new and old style big bearing ford 9" using 3/8" retaining bolts.
Rotor Thickness1"
Rotor I.D.2.78"
Rotor Backspace2.3"
Thread Pitch7/16"-20
FinishNatural
Axle Flange Offset2.36" - 2.50"
Rotor Material TypeCast Iron

Ratings & Reviews

4.4

61 Reviews

Overall Assessment

The product consistently receives positive feedback regarding its quality and practicality. Customers regularly noted the ease of installation and appreciated the thorough instruction video. The parts appear to be of high quality, fit well, and work as advertised, providing an upgrade over older brake systems and increasing safety with the included E-Brake. Many customers confirmed they would purchase again and recommend to others. However, some reported the need for additional modifications, found initial set up slightly tedious, and some parts missing. Despite these minor drawbacks, most found the product to be a great value for the price.

4.4

61 reviews

5

41

4

12

3

3

2

2

1

3

Most Liked Positive Review

4.0

Great Kit; Lousy Instructions

This is a 5-star kit with 1-star instructions. My buddy and I got them together largely through a trial and error process, comparing the parts to the blurry illustrations. Without any identification of the parts in the illustrations, the written instructions are nearly useless. The instructions should advise that the stock retainer plates should definitely be removed. Otherwise, the T-bolts aren't long enough. Finding the right combination of spacers (provided with the kit) in order to center the calipers over the rotors is a tedious process. I ended up using all the spacers in the kit. I found it necessary to position the calipers facing straight back instead of up and back, as the latter position left the top caliper bolt inaccessible because of proximity to my '32 Ford's frame rail. With all of that said, it's a great kit in terms of the parts. Now I can't wait to try them out!

Most Liked Negative Review

1.0

Horrible product

The instructions for this were horrible, the parking brake wouldn't adjust correctly and they are not anywhere near as flexible as they say they are. To bleed these brakes you have to take the calipers off. Overall a terrible product. The only great part was the customer support offered by Speedway. They were really helpful and I bought the Wilwood version instead.

Filter by Ratings

I would buy again

5.0

20 days ago

Jumpin Jehosaphat

MO

Verified

Works like it is advertised

Would Recommend

Very Complete and Good Quality

4.0

2 months ago

JJR

Lynn, MA

Verified

Not ready to install but I opened the package and inventoried the assembly. Very Complete kit and good quality parts. This kit will make the upgrade easier.

Would Recommend

I would buy again

5.0

7 months ago

JR

Phila,pa

Verified

Installation was easy and quality parts

Would Recommend

I would buy these again

5.0

7 months ago

Mr. Willys

Az

Verified

These worked out great,fit fine ,stop well. An upgrade to a hotrod project.

Some assembly required

5.0

8 months ago

Mr. Willys

Az

Verified

Should work just fine, not installed yet, project car

Helps me stop in the short shutdown areas.

5.0

8 months ago

Suncoast Mack

Hudson Fl

Verified

Easy install, worked better than expected.

Would Recommend

Worked with mods

3.0

10 months ago

Rpc

Zachary,la

Verified

Added disk brakes to new ford 9 in rearend. Had to drill out stud holes in rotor, had to enlarge center hole in rotor, and was told the system would work with 15 in rims. Had to shave the calipers about .020" to get rims to fit. Also added spacers behind rims to move wheel away from calipers.

Would Not Recommend

Would buy again!

3.0

12 months ago

Bert

Spokane Wa

Verified

I like these kits from speedway. Very cost effective way to put disc brakes on a 9" only down fall is the center hub diameter wont clear most axles. Ended up ordering custom axles so I would have the correct diameter but overall very happy with the kit.

Would Recommend

yes

5.0

a year ago

Redwhisper

Maine

Verified

39 Pickup street rod

Would Recommend

Work great on my 46 Ford Truck

5.0

a year ago

Russ

Maine

Verified

I used these in a 4 wheel disc setup on my 46 Ford truck. Excellent stopping power. Overall quite happy with my brakes. Straight forward install.

Would Recommend

Load More Reviews

Showing 10 of 61 reviews

Customer Impersonation Script