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Grade 8 Rear Control Arm Bolt Upgrade Kit for the 1964-1977 GM A-Body
This is the single-position bolt upgrade kit that replaces the tired factory fasteners at one rear control arm position on a 1964-1977 GM A-Body, and UMI also publishes it for the 1970-1974 GM F-Body Camaro and Firebird. Half inch Grade 8 bolts, nylon lock nuts and flat washers come zinc coated for corrosion resistance.
UMI's guidance is straightforward: when new control arms go in, the old bolts should not. The kit is designed to work with UMI A-arms, factory A-arms and arms from other manufacturers, which makes it the default fastener choice when a rear arm is replaced without a full four-arm rebuild.
Key Features
- Half inch Grade 8 bolts for one rear control arm position
- Nylon lock nuts and flat washers supplied with the bolts
- Zinc coating for corrosion resistance
- Suited to UMI arms, factory arms and many other brands
- Direct bolt-on replacement for the original fasteners
- Published by UMI for both the 1964-1977 A-Body and the 1970-1974 F-Body
Fitment
| Vehicle | Years |
|---|---|
| Buick Century | 1973-1977 |
| Buick Gran Sport | 1965-1967 |
| Buick GS | 1970-1972 |
| Buick GS 350 | 1968-1969 |
| Buick GS 400 | 1968-1969 |
| Buick GS 455 | 1970-1972 |
| Buick Regal | 1973-1977 |
| Buick Skylark | 1964-1972 |
| Buick Special | 1964-1969 |
| Buick Sportwagon | 1964-1972 |
| Chevrolet Chevelle | 1964-1977 |
| Chevrolet El Camino | 1964-1977 |
| Chevrolet Laguna | 1973-1976 |
| Chevrolet Malibu | 1964-1967 and 1973-1977 |
| Chevrolet Monte Carlo | 1970-1977 |
| Oldsmobile 442 | 1964-1971 |
| Oldsmobile Cutlass | 1964-1977 |
| Oldsmobile F85 | 1964-1977 |
| Oldsmobile Vista Cruiser | 1964-1972 |
| Pontiac Grand Am | 1973-1977 |
| Pontiac Grand Prix | 1969-1972 |
| Pontiac GTO | 1964-1977 |
| Pontiac Tempest | 1964-1970 |
| Pontiac LeMans | 1964-1977 |
| GMC Sprint | 1971-1972 |
| Chevrolet Camaro | 1970-1974 |
| Pontiac Firebird | 1970-1974 |
UMI's own product name refers to a lower hardware kit, while its application table also lists the 1970-1974 GM F-Body Camaro and Firebird. The manufacturer application table governs, so both platforms are published here.
UMI publishes year, make and model for this part number without a submodel, trim, engine or drivetrain breakdown, so the fitment tags on this listing stop at model level rather than inventing a trim. The one exception is the Impala SS, which UMI names directly.
Specifications
| Detail | Value |
|---|---|
| Kit scope | One rear control arm position. Replacing both the upper and lower rear arms needs the complete kit instead |
| Bolts | Half inch Grade 8 |
| Nuts and washers | Nylon lock nuts with flat washers |
| Finish | Zinc coating |
| Piece counts | UMI does not publish quantities for this part number. Two retailers list four bolts with four nylon lock nuts and washers, which is retailer evidence rather than a manufacturer specification and is recorded here as such |
| Material | Steel. Grade 8 is an SAE strength grade defined for steel fasteners |
| Compatibility | UMI states the kit works with UMI A-arms, factory A-arms and other brands |
| Direct bolt-on | Yes |
| Position | Rear suspension |
| Torque specification | UMI publishes no torque figure for this hardware kit and no dedicated installation sheet exists for it. Use the torque published in the instructions for the control arms being installed, or the factory service manual value for the vehicle. As a reference point, UMI's own 1964-1972 A-Body rear lower arm sheet calls for 72 ft-lb |
| Shipping weight and boxed dimensions | Recorded by UMI as not available |
| Country of manufacture | United States. UMI manufactures in Philipsburg, Pennsylvania |
| Manufacturer warranty | Two years from the original date of purchase against defects in materials and workmanship, to the original purchaser only and not transferable |
| Warranty exclusions | Misuse, abuse, neglect or accident, use beyond the design limits of the product, improper installation, acts of God, handling and shipping damage, any product altered, adjusted, tampered with or defaced, non-UMI components, incidental costs such as towing and labour, and normal wear items including bearings and bushings |
| Warranty document conflict | The packaged instruction sheet still carries an older all-caps disclaimer limiting coverage to freedom from defect at the time of purchase. UMI's live policies page publishes the current two year term and is the document summarised here. Neither is a Black Ops Auto Works warranty |
| Third-party component compatibility | UMI states it cannot guarantee compatibility or performance of its products with other components used alongside them, so confirm dimensions before mixing brands |
| Suitability versus warranty | UMI sells this kit so that new or refurbished rear control arms are installed on fresh Grade 8 fasteners rather than decades-old factory bolts. That describes what the part is built to do. Warranty eligibility is separate: UMI covers defects in materials and workmanship for two years and excludes damage from exceeding the design limits of the part, improper installation, and normal wear on bushings and bearings |
What's Included
- Half inch Grade 8 zinc coated bolts for one rear control arm position
- Half inch nylon lock nuts
- Flat washers
UMI publishes the contents by description rather than by count. Retailer listings for this part number state four bolts and four nylon lock nuts with washers, and that count is retailer evidence only, so it is not presented here as a manufacturer confirmed quantity.
About UMI Performance
UMI Performance builds chassis and suspension parts at 509 Hemlock Street in Philipsburg, Pennsylvania, using precision bent DOM tubing, laser cut steel, TIG and robotic welding and durable powder coat finishes. Alongside its arms and braces, UMI supplies matching Grade 8 fastener kits so that a suspension refresh does not end up reusing worn factory bolts.
Related Parts
FAQ
Does this cover both the upper and lower rear arms?No. This is the single-position upgrade kit. UMI's complete rear control arm bolt kit carries double the hardware and covers both the upper and lower rear positions.
What size and grade are the bolts?Half inch Grade 8, zinc coated, supplied with nylon lock nuts and flat washers.
How many pieces are in the kit?UMI does not publish a count for this part number. Retailers list four bolts and four nylon lock nuts with washers, which is retailer evidence rather than a manufacturer figure.
Will it work with arms from another brand?UMI states the kit works with UMI arms, factory arms and other brands. Confirm your arms use half inch mounting hardware first, because UMI does not guarantee compatibility with components it did not make.
Does it fit a second generation Camaro or Firebird?Yes. UMI publishes the 1970-1974 GM F-Body alongside the A-Body application for this part number.
What is the finish?Zinc coating, chosen for corrosion resistance on an exposed underbody fastener.
Is there an installation sheet for the kit?No. Follow the sheet supplied with the control arms being installed. UMI's 1964-1972 A-Body rear lower arm sheet, for example, calls for 72 ft-lb on the arm bolts.
Why replace the factory bolts at all?UMI's guidance is to avoid reusing old, worn bolts when installing aftermarket arms, since the clamp load at those joints is what keeps the rear suspension located.
Are these the front A-arm bolts?No. This kit is rear control arm hardware. UMI publishes a separate kit for the front upper and lower A-arms.
What warranty applies, and what is excluded from it?UMI publishes a two year warranty from the original date of purchase against defects in materials and workmanship, to the original purchaser only, and it is not transferable. The same policy excludes misuse, use beyond the design limits of the part, improper installation, acts of God, handling and shipping damage, any product that has been altered, adjusted, tampered with or defaced, components not made by UMI, incidental costs such as towing and labour, and normal wear items including bearings and bushings. UMI also states it cannot guarantee compatibility with other manufacturers' components. The sheet packed in the box still carries an older disclaimer that predates the current two year term, and the live policy page is the document that governs. Neither is a Black Ops Auto Works warranty.
Installation Instructions
- Check the kit contents against the arms being installed, and confirm your arms use half inch mounting hardware before starting.
- Support the car on jack stands under the frame, following the procedure in the instruction sheet for the control arms being fitted.
- Work one arm at a time so the rear axle stays located.
- Fit the new Grade 8 bolt with a flat washer, then the nylon lock nut, leaving the fastener loose.
- Load the suspension by relocating the stands to the rear axle before final tightening.
- Tighten to the torque published in the control arm instructions or the factory service manual value for the vehicle, since UMI publishes no torque figure for the fastener kit itself.
- Recheck the fasteners after the first few drives.
For a UMI A-Body rear lower arm, the manufacturer sheet publishing the arm torque is at https://static.speedwaymotors.com/pdf/1854015B.pdf.
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