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#91031902
Budget Ford 9 Inch Rear End Disc Brake Conversion Kit
- Disc brake stopping power for your Ford 9 inch rearend at nearly the same cost as rebuilding/replacing drum brakes
- This Ford 9 inch rear disc brake conversion kit includes two bolt-on caliper brackets, two 11-1/4" vented rotors, two GM metric style calipers (non-emergency brake), brake pads and hardware for increased stopping power
- Fits over an axle with maximum flange diameter of 6-1/4" O.D.
$399.99
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Product Summary
Ford 9 Inch, Rear Position, 11.25 Inch Rotor Diameter
- Disc brake stopping power for your Ford 9 inch rearend at nearly the same cost as rebuilding/replacing drum brakes
- This Ford 9 inch rear disc brake conversion kit includes two bolt-on caliper brackets, two 11-1/4" vented rotors, two GM metric style calipers (non-emergency brake), brake pads and hardware for increased stopping power
- Fits over an axle with maximum flange diameter of 6-1/4" O.D.
- Rotors have a 2.780" center hole with both 5 on 4-1/2" and 5 on 4-3/4" bolt circles
- Ford 9 inch rear disc brake kit 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
View Kit Components
Key Specs
| MFG. Part # | 91031902 |
| Position | Rear |
| Rotor Diameter | 11.25 Inch |
| Rotor Type | Vented |
| Caliper Pistons | One |
Need To Know
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Speedway Motors 91031902 Details
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 9 inch axles, as well as 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
- 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)
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"
Guides & Documents
Speedway Motors 91031902 Specifications
Speedway Motors 91031902 Specifications
| KEY SPECS | |
|---|---|
| MFG. Part # | 91031902 |
| Brand | Speedway Motors |
| Position | Rear |
| Rotor Diameter | 11.25 Inch |
| Rotor Type | Vented |
| Caliper Pistons | One |
| Caliper Finish | Natural |
| Color | Natural |
| Parking Brake Provision | No |
| Rotor Shape | Round |
| Hardware Included | Yes |
| Front Rotor Included | No |
| Front Caliper Included | No |
| Rear Caliper Included | Yes |
| Front Spindles Included | No |
| Master Cylinder Included | No |
| Brake Booster Included | No |
| Ford Bearing End Style | Big Ford (Old/New) |
| Rear Rotor Included | Yes |
| Bolt Pattern | 5 on 4.5" | 4.75" |
| GENERAL | |
| Sold in Quantity | Kit |
| Notes | Works new and old style big bearing Ford 9" using 3/8" retaining bolts. |
| Rotor Thickness | 1" |
| Finish | Natural |
| Axle Flange Offset | 2.36" - 2.50" |
Ratings & Reviews
4.7
74 Reviews
Customers attest to the quality and practicality of this product. They point to its strong and durable material, ease of installation and effectiveness, with some noting that the product was a significant upgrade from their previous kit. Despite the instruction manual being deemed vague by some users, they praise the usability and efficiency of the product once installed. While there were minor adjustments and small part modifications needed, the fit was otherwise perfect for most. Users recommend this product for its great price, solid features, and overall practicality. However, there were some negative reviews regarding missing installation instructions or parts. Overall, the product performed well and met customer expectations.
Ratings & Reviews
4.7
74 Reviews
Customers attest to the quality and practicality of this product. They point to its strong and durable material, ease of installation and effectiveness, with some noting that the product was a significant upgrade from their previous kit. Despite the instruction manual being deemed vague by some users, they praise the usability and efficiency of the product once installed. While there were minor adjustments and small part modifications needed, the fit was otherwise perfect for most. Users recommend this product for its great price, solid features, and overall practicality. However, there were some negative reviews regarding missing installation instructions or parts. Overall, the product performed well and met customer expectations.
4.7
74 reviews
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Most Liked Positive Review
4.0
Instructions Suck!
I knew from reading other people's reviews, that the instructions where rather lacking, but wow, they suck! I wouldn't recommend this kit for anybody with little or no mechanical experience. I've been working on stuff for over 40 years and a professional heavy equipment field service technician for over 25 years and it still took throwing the so called instructions away and using the trial and error method to install everything. Other than the lack of instructions, the only other issue was that the calipers won't clear one of the bracket mounting bolts. I tried positioning the bolt with the nut on the outside, towards the third member, as shown in the picture. When this didn't work, I tried placing the nut & washer on the rotor side. The caliper still wouldn't clear the bolt head and the rotor wouldn't seat, due to it's contacting the bolt. I finally purchased a couple button head bolts, placed the button head toward the caliper, left the washer out and after torquing the bolt to specifications, I cut the bolt off flush with the lock nut...
Most Liked Negative Review
1.0
I would not buy this product. Nor would I recommend it
Needs a lot of quality control, this kit needs a lot to be desired. The only kit I saw that does not come with hoses. There 8" hose kit is to short to fit on their 9" housing without going crazy long with steel line. Other than modifications to calipers and cutting hardware to fit I guess you can say it's questionable. Not trying to pick it apart, just telling my experience.
Filter by Ratings
Yes
5.0
2 months ago
The junk
Patterson ca
Verified
They was very helpful
Would Recommend
Great product, as described
5.0
3 months ago
Ferg
Antigo, WI
Verified
I bought a ford 9" from Speedway, wanted to go disc, so upgraded to this kit. Great quality. Great product
Would Recommend
I definitely would buy again
5.0
3 months ago
T-Body
Sardinia ohio
Verified
Easy installation
Would Recommend

Definitely buy again
5.0
4 months ago
T-body
Sardinia ohio
Verified
Very easy installation
Would Recommend
Fit as it should
5.0
4 months ago
87MonteSS
IL
Verified
All parts fit as they should.
Would Recommend
Great price for the quality
5.0
9 months ago
Rusty
Denver , NC
Verified
Very easy to install. Seems to be of good quality.
Would Recommend
Yes
5.0
11 months ago
Fast 28
Maryland
Verified
Used it in my dirt street stock.
Would Recommend
I will buy more from speedway
5.0
a year ago
dbsbb
Palmdale CA
Verified
Rear leaf springs
Would Recommend
Good buy for the money.
5.0
a year ago
KWD
Michigan
Verified
This is about a 6 pack to install. After one side is completed it is a breeze. I had to do some machining on the rotors to get them to fit my axle, that was fun. When installing this kit you'll have a bunch of spacers for the caliper brackets, you may curse at it for a minute or two, but they DO send you enough to get the job done. I would love to pay an extra few bucks for the option of painted calipers, red or black would be fine. other than that, good kit!
Would Recommend



Yes well fit
5.0
a year ago
Jack
Woodstock NY
Verified
Great stopping power
Would Recommend
Showing 10 of 74 reviews

