Ford 9 Inch Bolt-On Rear Disc Brake Kit w/ E-Brake
Ford 9", Rear Position, Dual: 5 on 4.5" | 4.75" Bolt Pattern, 11.25 Inch Rotor Diameter
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As featured on Classic Truck’s Week to Wicked. Watch the transformation here!
If you don't want to spend an arm and a leg on a rear disc brake kit and still have to weld the bracket on, we've got you covered. This kit includes bolt-on caliper brackets, 11-1/4" vented rotors, 78-88 GM emergency brake calipers, brake pads and hardware.
- Fits both 5 on 4-1/2" and 5 on 4-3/4" bolt circles
- For Ford passenger car axles ONLY
- Fits axle with maximum flange diameter of 6-1/4" O.D.
- For 15" and larger disc brake wheel applications ONLY
NOTE: This bolt on brake kit is designed to be used on 8" and 9" housings using 3/8" retaining bolts. If you want to use it on a 9" housing with 1/2" bolts, you will need to use the 3/8" hardware to do so. 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".
910-31921 Instructions (PDF)
With emergency brake calipers threaded to accept 7-16"-20 banjo bolt.
- "Old-style" big bearing 9" Ford axle
- "New-style" big bearing 9" Ford axle
- 8" 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"
The inside diameter of this rotor will accept an axle flange that has a diameter of 6-1/4" or smaller. If your axle flange exceeds 6-1/4" in diameter, you will need machine your axle flange to decrease your axle flange diameter to fit this rotor as necessary.
When utilizing an aftermarket axle with disc brake conversion kits, it may be necessary to reduce the diameter of the axle flange to a diameter necessary to adequately fit inside the required Clearance I.D. that the brake hat/brake rotor will require. (see above diagram for illustration)
What's In The Kit
Speedway Replacement 11-1/4 Inch Rear Brake RotorPart # 91031039Qty x 2
GM Metric Disc Brake to 9 Inch Ford Bracket SetPart # 91031981Qty x 1
Ford 9 Inch Brake Bolt KitPart # 91031981-2Qty x 1
1978-Up GM Metric Emergency Brake Caliper, LH, 5.45 Mount BoltsPart # 91031046-LQty x 1
1978-Up GM Metric Emergency Brake Caliper, RH, 5.45 Mount BoltsPart # 91031046-RQty x 1
Instruction Sheet 91031902/91031921Part # 910319.INSTQty x 1
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Q & A
Day 1 afternoon update of the Speedway Motors and Classic Trucks Week to Wicked classic Chevy project.
Now that Project Chevelle is finally making real power, we want it all to get to the ground without breaking anything. Follow along as we install a 9-inch housing, third member, and some trick tubular control arms!
The E-Stopp Electric E-Brake is an electronic push-button activated emergency brake option where the visible element is small and compact, and can replace the traditional hand or foot-operated emergency brakes.
Learn how to assemble a rear axle assembly as we put together ours for the 410 Sprint Car Build. Our team of builders continues to make progress on the car!
Today on our 410 sprint car, the guys are assembling the front axle. The process can be a bit messy, but the finished product is so worth it!