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#91031931
Weld-On Rear Disc Brake Kit, 1978-88 GM Caliper, 3 Inch Backspace
- Replace those old drum rear brakes with modern disc brakes using this universal weld on disc brake kit
- Features GM Metric calipers with massive 2.38" piston size which provide excellent braking in a compact size
- 11.75" OD vented rotors which are .81" thick ensure cool operation for fade free braking performance
$293.99
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Product Summary
Universal Fit, Rear Position, 11.75 Inch Rotor Diameter
- Replace those old drum rear brakes with modern disc brakes using this universal weld on disc brake kit
- Features GM Metric calipers with massive 2.38" piston size which provide excellent braking in a compact size
- 11.75" OD vented rotors which are .81" thick ensure cool operation for fade free braking performance
- This complete kit includes calipers, rotors, brake pads, brake hats, caliper slide bolts, and caliper brackets
- The 3" backspace steel brake hat accommodates 5 on 4-1/2, 4-3/4", and 5 on 5" bolt circles
Comes as a Kit
View Kit Components
Key Specs
| MFG. Part # | 91031931 |
| Position | Rear |
| Wheel Bolt Pattern (in.) | 5x4.5 in. | 5x4.75 in. |
| Wheel Bolt Pattern (mm) | 5x114.3 mm | 5x120.65 mm |
| Rotor Diameter | 11.75 Inch |
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Speedway Motors 91031931 Details
Replace those old drum brakes with modern rear disc brakes. Mounts .81" x 11-3/4" Pro-lite vented iron rotors and calipers to 3" tube rear end. Complete with rotors, hats, metric calipers (7/16"-20 inlets), brackets, brake pads, caliper brackets and slider bolts.
Steel hat fits 5 lug hubs with 4-1/2", 4-3/4", or 5" bolt circle.
- Caliper Brackets (2)
- Weld onto a 3" axle tube
- Rotors (2)
- GM-style .81" x 11-3/4", 8 on 7" bolt pattern
- Straight vanes, 8 lbs. each
- Rotor Hats (2)
- Stamped steel, 3" backspace
- 3.06" center hole, 5.83" I.D., 1/2" stud holes, 2 lbs.
- Rotor Bolt and Nut Kit (2)
- Caliper Slider Bolts (4)
- Brake Pads (2 sets)
- Street compound, little metallic, long rotor and pad life
- Calipers - 1978-88 GM Metric (L & R)
- 7/16"-20 inlet
- Cast iron body, 2.38" single piston
- Saves 3.5 lbs. per side compared to '69-'77 GM calipers
Kit Inclues:
- (2) GM Metric Caliper Brackets
- (2) Vented Brake Rotors
- (2) Stamped Steel Brake Rotor Hat
- (2) Rotor Hat Bolt Set
- (4) Slider Bolts
- (2) Pairs of Brake Pads
- (1) Left Metric Caliper
- (1) Right Metric Caliper
- (1) Instruction Sheet
Charts
910-31931 Instructions (PDF)
Instructions (PDF)
Guides & Documents
Speedway Motors 91031931 Specifications
Speedway Motors 91031931 Specifications
| KEY SPECS | |
|---|---|
| MFG. Part # | 91031931 |
| Brand | Speedway Motors |
| Position | Rear |
| Wheel Bolt Pattern (in.) | 5x4.5 in. | 5x4.75 in. |
| Wheel Bolt Pattern (mm) | 5x114.3 mm | 5x120.65 mm |
| Rotor Diameter | 11.75 Inch |
| Rotor Type | Vented |
| Caliper Pistons | One |
| Caliper Finish | Natural |
| Parking Brake Provision | No |
| Minimum Recommended Wheel Diameter | 15 Inch |
| Rotor Shape | Round |
| Hardware Included | Yes |
| Rotor Style | Plain Face |
| Front Rotor Included | No |
| Front Rotor Diameter | 11.75 Inch |
| Front Caliper Included | No |
| Rear Caliper Included | Yes |
| Front Spindles Included | No |
| Master Cylinder Included | No |
| Brake Booster Included | No |
| Brake Hoses Included | No |
| Rear Rotor Included | Yes |
| Finish | Natural |
| Rotor Hat Bolt Pattern | 8 x 7.00" |
| Color | Natural |
| Front Caliper Finish | Natural |
| Bolt Pattern | 5x4.5 | 5x4.75 | 5x5 |
| GENERAL | |
| Sold in Quantity | Kit |
| Notes | Includes rotors, rotor hats, caliper brackets, calipers, pads, and hardware. |
| Rotor Thickness | 0.81" |
| Rotor Backspace | 3" |
| Thread Pitch | 7/16"-20 |
| Centerline of Holes | 5.5" |
| Rotor Material Type | Cast Iron |
Ratings & Reviews
4.3
15 Reviews
Customers appreciate the product's performance, noting its successful application in various builds. Praised for its practicality and great design, the kit enhances vehicle braking systems, effectively upgrading drum brakes. Some customers found the fit of the parts perfect while others reported needing minor alterations, demonstrating adaptability and usability in a range of situations. Despite some slight criticism on the clarity of instructions, the cost-efficiency exuded by the product compared to its competitors was highlighted. However, some customers noted a need for more robust quality of certain components to enhance safety. All in all, customers expressed a willingness to purchase it again, acknowledging its positive performance and value.
Ratings & Reviews
4.3
15 Reviews
Customers appreciate the product's performance, noting its successful application in various builds. Praised for its practicality and great design, the kit enhances vehicle braking systems, effectively upgrading drum brakes. Some customers found the fit of the parts perfect while others reported needing minor alterations, demonstrating adaptability and usability in a range of situations. Despite some slight criticism on the clarity of instructions, the cost-efficiency exuded by the product compared to its competitors was highlighted. However, some customers noted a need for more robust quality of certain components to enhance safety. All in all, customers expressed a willingness to purchase it again, acknowledging its positive performance and value.
4.3
15 reviews
5
9
4
3
3
2
2
1
1
0
Most Liked Positive Review
5.0
I would buy again
Used the kit on an 8.8 Ford rear end.the brackets are for a 3 inch axle tube only and needed modified to use on the smaller 8.8 axle tubes.
Most Liked Negative Review
3.0
Would buy again
Rat Rod pick up converted a s10 rearmed to disc brakes. Only complaint is had to grind on metal part of pads to get caliper bolts aligned in weld on brackets and kit should include brake pad spacers for .810 rotors or put 1.25 rotors in kit
Filter by Ratings
Yes
5.0
8 months ago
Galbreath Motor Sports
Jonesboro ar
Verified
Product as described
Would Recommend
yes sir good item
2.0
a year ago
doug53
missouri
Verified
on my 53 3100
Would Recommend
Great product
5.0
a year ago
Jeff
Midway Georgia
Verified
Great product easy to assemble
Would Recommend
I love this kit
5.0
a year ago
L
Michigan
Verified
Very nice weld on kit for my 9 inch. I like the lighter brake rotors for rear use on my c10
Would Recommend
I would buy this product again
5.0
3 years ago
Jeff
Alabama
Verified
Fit as slit should
Would Recommend
I would definitely buy this kit again for another build
5.0
5 years ago
Roadster
Dumas, Tx.
Verified
this kit works really good
Would Recommend
Fit perfectly on my 12 bolt
5.0
6 years ago
Bad C-10
Missouri
Verified
Nice upgrade
Would Recommend
For perfectly on my 12 bolt.
5.0
6 years ago
Bad C-10
Missouri
Verified
Wanted good upgrade over drums.
Would Recommend
Would buy again
3.0
8 years ago
Ed B
New Berlin Il.
Verified
Rat Rod pick up converted a s10 rearmed to disc brakes. Only complaint is had to grind on metal part of pads to get caliper bolts aligned in weld on brackets and kit should include brake pad spacers for .810 rotors or put 1.25 rotors in kit
Would Recommend
I would buy again
4.0
8 years ago
J
York pa
Verified
Great product some fine tuning but good design
Would Recommend
Showing 10 of 15 reviews
Questions & Answers
11 Questions • 10 Answers
Questions & Answers
11 Questions • 10 Answers
Will this work on ford 8.8 housing with strange c-clip eliminators?
by Matt
• 9 years ago
1 answer
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If this kits is used on a mopar 8 3/4" rear.. does it require the switch to the green ( non adjustable bearings?)
by Ken
• 10 years ago
1 answer
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What does the backspace means
by Sean
• 10 years ago
1 answer
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How do the calipers and the caliper bracket go together? I'm puzzled trying to assemble these. Picture instructions would be very helpful!
by Jay
• 11 years ago
1 answer
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Can I get a hat with a 5 lug on 5.5" hole circle?
by AAshby
• 11 years ago
1 answer
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Is there a option for drilled and slotted rotors with this kit? Is there a option to upgrade to drilled and slotted rotors with this kit?
by nate31
• 11 years ago
1 answer
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will this kit work with 15" wheels
by x37v
• 12 years ago
1 answer
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will this work on a 1964 impala
by jeremiah47j
• 12 years ago
1 answer
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What is the torque spec on the 5/16 bolts that hold the rotor on? Should the nuts face in or out? A picture in the instructions would be a LOT of help
by victor906
• 13 years ago
1 answer
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Is this kit fits on my chevy 80 with dana 30 axle?
by Garagem39
• 13 years ago
1 answer
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10 of 11 questions shown