1970-1981 Camaro Firebird Trans Am Rear Leaf Spring Isolator and Installation Hardware Kit, UMI-2627

Hawks Motorsports is proud to offer our clients this : 1970-1981 Chevrolet Camaro, Pontiac Firebird, Formula and Trans Am Rear Leaf-Spring Isolator and Installation-Hardware Kit from UMI Performance.

UMI Performance #2627 provides the primary axle-clamping hardware, polyurethane isolator pads and front spring-eye mounting bolts required when installing compatible stock-location rear leaf springs in a 1970-1981 second-generation GM F-body.

The kit is designed to work with UMI Performance #2620 rear leaf springs and other compatible original-style or aftermarket stock-location multi-leaf springs.

UMI-2627 replaces worn, compressed or deteriorated factory leaf-spring isolators with four black performance-polyurethane isolator pads. These pads cushion and locate the rear leaf springs where they meet the axle mounting perches and lower spring plates.

Four heavy-duty zinc-plated U-bolts replace the original combination of factory U-bolts and T-bolts. Using two U-bolts on each side provides a more consistent clamping arrangement around the rear axle tubes and is better suited to the increased loads produced by performance and high-horsepower applications.

The kit also includes new Grade 8 front spring-eye through-bolts, flat washers and nylon-insert locking nuts. These bolts connect the front eye of each rear leaf spring to the original-style front spring mounting pocket.

UMI’s published instructions identify the front spring-eye bolts as 1/2-13 × 5 inches and specify a 50 ft-lb tightening value. The instructions specify a 45 ft-lb final tightening value for the spring-plate U-bolt nuts.

UMI-2627 is suitable for restoration, street-performance, Pro-Touring, autocross, road-course and high-horsepower applications retaining the compatible factory-style rear leaf-spring mounting arrangement.

Complete Kit Contents

UMI’s published instructions identify the following components:

• One four-piece black polyurethane leaf-spring isolator set
• Four heavy-duty rear axle U-bolts
• Eight 7/16-inch thick-pattern U-bolt washers
• Eight high-hex U-bolt nuts
• Two 1/2-13 × 5-inch Grade 8 front spring-eye bolts
• Two 1/2-inch flat washers
• Two 1/2-13 nylon-insert locking nuts
• Components for the driver and passenger sides

Polyurethane Leaf-Spring Isolators

The included polyurethane isolator package provides four pads:

• Two upper isolator pads
• Two lower isolator pads
• One upper and one lower pad for each rear leaf spring
• Molded locating provisions for compatible factory-style spring and axle-perch alignment

The upper isolator fits between the top of the leaf spring and the axle spring perch. The lower isolator fits between the bottom of the leaf spring and the original-style lower spring plate.

The leaf-spring locating pin must properly engage the isolator and axle-perch mounting arrangement. Both sides must be fully seated before tightening the U-bolts.

The polyurethane isolators are intended to replace original pads that may be:

• Crushed
• Split
• Hardened
• Oil-soaked
• Deformed
• Missing
• Deteriorated from age
• No longer properly locating the leaf spring

Heavy-Duty U-Bolt Conversion

Many original second-generation F-body leaf-spring installations used a combination of U-bolts and T-bolts to secure the axle, isolators, leaf springs and lower spring plates.

UMI-2627 replaces that arrangement with four full U-bolts:

• Two U-bolts on the driver side
• Two U-bolts on the passenger side
• Eight matching high-hex nuts
• Eight matching thick-pattern washers
• Zinc-plated finish on the U-bolts
• Increased support for street and performance applications

UMI specifically identifies this conversion as an upgrade capable of better handling the loads generated by high-horsepower vehicles while remaining suitable for stock and restoration applications.

Front Spring-Eye Hardware

The kit includes two new front leaf-spring through-bolts:

• Two 1/2-13 × 5-inch Grade 8 bolts
• Two 1/2-inch flat washers
• Two 1/2-13 nylon-insert locking nuts
• One bolt assembly for each rear leaf spring
• Published UMI tightening value of 50 ft-lbs

These bolts pass through the front spring-eye bushing and the original-style front leaf-spring mounting pocket.

The kit does not include the three smaller fasteners that attach each front spring pocket to the vehicle’s body structure.

Compatible Rear Leaf Springs

UMI-2627 is designed for use with:

• UMI Performance #2620 rear lowering leaf springs
• Compatible original GM rear multi-leaf springs
• Factory-style replacement multi-leaf springs
• Stock-location performance rear leaf springs
• Compatible Camaro rear leaf springs
• Compatible Firebird rear leaf springs
• Compatible Formula rear leaf springs
• Compatible Trans Am rear leaf springs
• Compatible Turbo Trans Am rear leaf springs

The rear springs must retain the compatible factory-style width, axle-perch location, front spring-eye dimensions and lower spring-plate arrangement.

Important Product Information

UMI-2627 is an isolator and installation-hardware kit. It is not:

• A rear leaf-spring set
• A rear lowering-spring set
• A rear shackle kit
• A rear shackle-bushing kit
• A front leaf-spring pocket set
• A set of front spring-pocket-to-body bolts
• A lower spring-plate set
• A shock mounting kit
• A traction-bar kit
• A lowering-block kit
• A rear sway-bar installation kit
• A rear axle mounting-perch set
• A complete rear suspension system

Rear shackles and rear spring-eye bushings are available separately. UMI #2625 provides polyurethane rear shackle bushings and shackles, while UMI #2626 provides Delrin bushings and heavy-duty shackles.

UMI-2627 does not alter the advertised ride height or spring rate. Ride height and spring rate are determined by the selected leaf springs and any separately installed lowering blocks.

4. KEY FEATURES

• Fits 1970-1981 Chevrolet Camaro models
• Fits 1970-1981 Pontiac Firebird models
• Fits 1970-1981 Pontiac Firebird Esprit models
• Fits 1970-1981 Pontiac Firebird Formula models
• Fits 1970-1981 Pontiac Firebird Trans Am models
• Fits applicable 1980-1981 Turbo Trans Am models
• Manufacturer-listed for all 1970-1981 GM F-body models
• Designed for second-generation GM F-body rear suspension
• Works with UMI Performance #2620 rear leaf springs
• Works with compatible stock-location rear leaf springs
• Works with compatible original GM multi-leaf springs
• Works with compatible factory-style replacement leaf springs
• Works with compatible performance multi-leaf springs
• Includes four black polyurethane isolator pads
• Includes upper and lower isolators for both rear springs
• Replaces worn factory leaf-spring isolator pads
• Polyurethane construction provides durable spring support
• Helps properly locate the leaf springs beneath the rear axle
• Includes four heavy-duty rear axle U-bolts
• Uses two U-bolts per side
• Replaces the original T-bolt and U-bolt arrangement
• Better suited to loads generated by high-horsepower applications
• Zinc-plated U-bolt finish
• Includes eight thick-pattern U-bolt washers
• Includes eight high-hex U-bolt nuts
• Includes two Grade 8 front spring-eye bolts
• Front bolts measure 1/2-13 × 5 inches
• Includes two 1/2-inch flat washers
• Includes two 1/2-13 nylon-insert locking nuts
• Provides components for both rear leaf springs
• Suitable for restoration vehicles
• Suitable for street-performance applications
• Suitable for Pro-Touring builds
• Suitable for autocross applications
• Suitable for road-course-inspired vehicles
• Suitable for drag-strip and high-horsepower applications
• Retains the compatible factory-style mounting arrangement
• UMI specifies 50 ft-lbs for the front spring-eye bolts
• UMI specifies 45 ft-lbs for the spring-plate U-bolt nuts
• Direct-fit configuration for verified applications
• Manufactured in the USA
• Does not include rear leaf springs
• Does not include rear shackles
• Does not include rear shackle bushings
• Does not include front spring mounting pockets
• Does not include lower spring plates
• Does not include shock hardware
• Does not include lowering blocks
• Does not change the advertised spring rate
• Does not provide an advertised ride-height change
• Not designed for relocated or mini-tub leaf-spring systems
• Not designed for four-link or rear coilover conversions
• Not designed for 1967-1969 first-generation F-body models
• Not designed for 1982-2002 third- or fourth-generation F-body suspension
• One kit services one complete vehicle
• UMI Performance manufacturer part #2627
• Hawks Motorsports part #UMI-2627

5. MODEL INTERCHANGE AND FITMENT

UMI Performance lists UMI-2627 specifically for the 1970-1981 GM F-body platform.

The kit fits compatible second-generation Camaro and Firebird models retaining the original-style stock-location rear multi-leaf suspension arrangement.

Chevrolet Camaro Applications

• 1970 Chevrolet Camaro
• 1971 Chevrolet Camaro
• 1972 Chevrolet Camaro
• 1973 Chevrolet Camaro
• 1974 Chevrolet Camaro
• 1975 Chevrolet Camaro
• 1976 Chevrolet Camaro
• 1977 Chevrolet Camaro
• 1978 Chevrolet Camaro
• 1979 Chevrolet Camaro
• 1980 Chevrolet Camaro
• 1981 Chevrolet Camaro

Includes applicable:

• Camaro Base
• Camaro Sport Coupe
• Camaro Rally Sport
• Camaro RS
• Camaro Super Sport
• Camaro SS
• Camaro Type LT
• Camaro LT
• Camaro Berlinetta
• Camaro Z28
• Factory appearance and performance packages retaining stock-location rear leaf springs

Camaro Trim Notes

• Super Sport and SS applications include applicable 1970-1972 models.
• Rally Sport and RS fitment applies wherever the package was offered with the compatible rear suspension.
• Type LT and LT fitment applies to applicable models.
• Berlinetta fitment applies to 1979-1981 models.
• Z28 fitment includes 1970-1974 and 1977-1981 models.
• The Camaro Z28 was not offered for the 1975 or 1976 model years.
• Engine and transmission selection do not normally affect fitment when the original-style rear suspension is retained.

Pontiac Firebird Applications

• 1970 Pontiac Firebird
• 1971 Pontiac Firebird
• 1972 Pontiac Firebird
• 1973 Pontiac Firebird
• 1974 Pontiac Firebird
• 1975 Pontiac Firebird
• 1976 Pontiac Firebird
• 1977 Pontiac Firebird
• 1978 Pontiac Firebird
• 1979 Pontiac Firebird
• 1980 Pontiac Firebird
• 1981 Pontiac Firebird

Includes applicable:

• Firebird Base
• Firebird Esprit
• Firebird Formula
• Firebird Trans Am
• Turbo Trans Am
• Trans Am Special Edition
• Firebird appearance packages
• Factory performance packages retaining stock-location rear leaf springs

Firebird Trim Notes

• Firebird Esprit applications include applicable 1970-1981 models.
• Firebird Formula applications include applicable 1970-1981 models.
• Trans Am applications include applicable 1970-1981 models.
• Turbo Trans Am fitment applies to compatible 1980-1981 models.
• Special Edition and appearance-package fitment is unchanged when the compatible stock-location rear leaf-spring arrangement is retained.
• Engine, transmission and rear brake configuration do not normally change fitment.

Important Fitment Notes

• UMI-2627 is intended specifically for 1970-1981 second-generation GM F-body models.
• The vehicle must retain a compatible stock-location rear leaf-spring suspension.
• The rear axle must remain mounted above the leaf springs in the original-style position.
• The kit is intended for compatible multi-leaf rear springs.
• The leaf springs must have compatible front spring-eye dimensions.
• The rear axle perches must accept the included isolators and locating arrangement.
• The original-style lower spring plates must accept the supplied U-bolts.
• The rear axle tubes must have compatible dimensions.
• The leaf-spring center pins must properly engage the isolator and axle-perch arrangement.
• Both upper and lower isolators must seat properly.
• The U-bolts must sit squarely around the axle tubes.
• The lower spring plates must not be bent, cracked or severely corroded.
• The axle perches must not be cracked, distorted or improperly welded.
• The leaf-spring center pins must not be loose, broken or damaged.
• Non-original rear axles may use different axle-tube diameters, perches or spring-plate dimensions.
• Confirm compatibility when installing a Ford 9-inch, fabricated housing or other non-original rear axle.
• Confirm compatibility when the axle perches have been replaced or relocated.
• Confirm compatibility when using custom or competition leaf springs.
• Mini-tub conversions with inward-relocated leaf springs are not standard UMI-2627 applications.
• Four-link, torque-arm and rear coilover conversions are not compatible.
• UMI-2627 does not fit 1967-1969 Camaro or Firebird models.
• UMI #2727 is the corresponding installation kit for manufacturer-verified 1967-1969 F-body applications.
• UMI-2627 does not fit 1968-1974 GM X-body models.
• UMI #2727 is the corresponding installation kit for compatible first-generation F-body and specified X-body applications.
• UMI-2627 does not fit 1982-1992 third-generation Camaro or Firebird models.
• UMI-2627 does not fit 1993-2002 fourth-generation Camaro or Firebird models.
• Third- and fourth-generation F-body models do not use this factory rear leaf-spring arrangement.

6. INSTALLATION NOTES

• Read the complete UMI Performance installation instructions before beginning.
• Verify that the package is UMI part #2627.
• Verify that all listed components are present.
• Confirm that the vehicle is a 1970-1981 Camaro or Firebird.
• Confirm that the vehicle retains compatible stock-location rear leaf springs.
• Inspect the rear leaf springs before disassembly.
• Do not install damaged, cracked, severely corroded or broken leaf springs.
• Inspect the front spring-eye bushings.
• Inspect the rear spring-eye bushings and shackles.
• Inspect both front spring mounting pockets.
• Inspect the three body-mounting fasteners securing each front spring pocket.
• Inspect the rear axle spring perches.
• Inspect both lower spring plates.
• Inspect the lower shock-mounting points.
• Inspect the leaf-spring locating pins.
• Correct damaged or improperly repaired mounting components before installation.
• Park the vehicle on a solid, level surface.
• Chock the front wheels.
• Safely raise the rear of the vehicle.
• Support the vehicle with properly rated jack stands.
• Support the vehicle by the chassis near the front leaf-spring mounting area.
• Keep the rear axle independently supported.
• Never work beneath a vehicle supported only by a hydraulic jack.
• Remove the rear wheels for proper access.
• Disconnect the lower rear shock mounts from the spring plates.
• The upper shock mounts may remain connected according to UMI’s procedure.
• Support the rear axle before removing the spring-plate fasteners.
• Remove the original U-bolt and T-bolt nuts.
• Remove the lower spring plates.
• Raise the axle only far enough to separate it from the leaf springs.
• Do not stretch the rear brake hose.
• Do not damage the axle brake lines.
• Original isolators may adhere to the springs or axle perches.
• Remove all deteriorated isolator material.
• Clean the spring, axle-perch and lower-plate contact surfaces.
• Remove loose rust and debris that could prevent proper seating.
• Support the leaf spring before removing its front mounting pocket.
• Remove the three fasteners attaching the front spring pocket to the body.
• Remove the original front spring-eye through-bolt.
• Install the supplied 1/2-13 × 5-inch Grade 8 front spring-eye bolt.
• Install the supplied flat washer beneath the nylon-insert locking nut.
• UMI’s published instructions specify 50 ft-lbs for the front spring-eye bolt.
• Follow the current instructions supplied with the product if they differ from an older publication.
• Position the upper polyurethane isolator between the leaf spring and axle perch.
• Make certain the leaf-spring locating pin engages the isolator correctly.
• Lower the axle carefully until the spring and isolator seat in the axle perch.
• Confirm that the axle is correctly positioned before continuing.
• Install the supplied U-bolts around the axle tube.
• Install the lower polyurethane isolator beneath the leaf spring.
• Reinstall the compatible lower spring plate.
• The original brake line may require slight repositioning to clear the U-bolt replacing the factory T-bolt.
• Do not kink, flatten or sharply bend a brake line.
• Confirm clearance between each U-bolt and the axle brake lines.
• Install the supplied thick-pattern washers and high-hex nuts.
• Tighten the four spring-plate nuts gradually.
• Use an alternating crisscross pattern.
• Draw the spring plate upward evenly.
• Do not fully tighten one nut while the others remain loose.
• Confirm reasonably equal thread engagement on all U-bolt legs.
• UMI’s published instructions specify a final spring-plate nut torque of 45 ft-lbs.
• Repeat the procedure on the opposite side.
• Reconnect the lower shock mounts.
• Confirm that the shocks, sway bar, brake hose and parking-brake cables have adequate clearance.
• Confirm that the rear axle remains centered on both leaf springs.
• Reinstall the wheels using the applicable wheel-fastener procedure.
• Lower the vehicle carefully.
• Inspect the completed installation before road testing.
• Listen for movement, clunks or other signs of an improperly seated component.
• Reinspect the U-bolts and spring plates after the initial suspension-settling period.
• Periodically inspect the U-bolts, isolators, spring plates and mounting pockets as part of normal suspension maintenance.