The Ultimate Guide to 79 Trans Am Suspension Parts: What You Need to Know

Restoring or upgrading a 1979 Pontiac Trans Am often starts with the suspension. The ’79 Trans Am is beloved for its iconic styling and handling, but decades of wear can leave the original suspension sagging, loose, or just plain tired. Whether you're aiming for a factory-correct restoration or a performance-oriented setup, choosing the right suspension parts is critical. This guide covers the key components, what to look for, and how to make smart buying decisions for your 79 Trans Am suspension.

Understanding the 1979 Trans Am Suspension System

The 1979 Trans Am came from the factory with a fairly conventional front suspension featuring unequal-length A-arms, coil springs, and a sway bar. The rear used a live axle on leaf springs with staggered shocks to control axle hop. While adequate for its time, the stock setup can be improved significantly for better ride quality, cornering, and braking. Upgrading the suspension also helps modern tires and drivetrain modifications work safely.

Front Suspension Components

The front end of a 79 Trans Am consists of upper and lower control arms, coil springs, shock absorbers (usually mounted inside the spring), a stabilizer bar, and steering knuckles. Common wear items include ball joints, bushings, and tie rods. When replacing these parts, you'll choose between OEM-style replacements (often Moog or AC Delco) and performance upgrades (like tubular control arms with polyurethane bushings).

Rear Suspension Components

The rear suspension uses leaf springs with multiple leaves, shock absorbers mounted behind the axle, and a sway bar (if equipped). Key parts include the leaf springs themselves, shackles, bushings, and shocks. For improved handling, many owners swap to aftermarket leaf springs with a lower arch or multi-leaf designs for better load capacity and reduced axle wrap.

Suspension Parts to Consider for Your 79 Trans Am

Shocks and Struts

Shocks are the most transformed upgrade for any suspension. For the 79 Trans Am, you have several options:

• Gas-charged shocks (e.g., KYB Gas-A-Just) offer improved damping over stock and are a good budget upgrade.
• Adjustable shocks (e.g., QA1 or Viking) allow you to tune compression and rebound for street or track use.
• Coilover conversions replace the front coil spring and shock with a single adjustable unit, giving ride height and damping control. These are popular for custom builds but require more work.

For the rear, consider shocks with a remote reservoir if you drive hard. Standard twin-tube shocks work fine for street use.

Springs

Coil springs and leaf springs determine ride height and spring rate. For the front:

• Factory replacement springs (e.g., Moog CC639 or CC640) maintain stock ride height and rate.
• Lowering springs (e.g., Eibach Pro-Kit or Hotchkis) drop the car 1-2 inches for a more aggressive stance and lower center of gravity. Make sure they match your shock travel.
• Variable-rate springs provide a softer ride over minor bumps but stiffen up during cornering.

For the rear leaf springs, you can buy new OEM-style units (like those from Eaton Detroit Spring) or aftermarket multi-leaf packs with higher rates. Re-arching old springs is possible but not recommended for performance builds.

Control Arms and Bushings

Factory control arms use rubber bushings that deflect and wear over time. Upgrading to tubular control arms with polyurethane or Delrin bushings reduces deflection and improves alignment stability. Polyurethane is a popular choice for street cars—it's stiffer than rubber but still forgiving. For track use, spherical bearings (heim joints) give maximum precision but transmit noise and vibration.

Upper control arms on the 79 Trans Am often have non-adjustable shims for caster/camber. Aftermarket arms with adjustable ball joint mounts allow you to dial in alignment without shims. Lower control arms are simpler, but upgrading to boxed or tubular lowers reduces flex under hard braking.

Sway Bars

A thicker sway bar reduces body roll during cornering. The 79 Trans Am came with a 1.125" front bar and 0.75" rear bar in some trims. Aftermarket bars (like Hellwig or Addco) in 1.25" or 1.375" front and 1" rear dramatically improve flat cornering. Pair with polyurethane bushings and end links for maximum effect.

Leaf Spring Replacement Parts

Leaf springs wear by taking a permanent set (sag) and losing arch. New leaf springs restore ride height and handling. Also replace the leaf spring bushings (often press-in) and shackles (the brackets that attach the spring to the frame). Greasable polyurethane bushings are available for longer life.

Steering Components

Suspension upgrades are incomplete without addressing steering. The ’79 Trans Am uses a recirculating-ball steering box with a pitman arm, center link, and tie rods. Worn tie rods or a loose steering box will make a good suspension feel sloppy. Replace inner and outer tie rods (Moog ES627R, ES628L, etc.) and consider a steering box quick-ratio upgrade (e.g., from a later model or a performance rebuild).

Choosing OEM vs. Performance Parts

Your choice depends on your goal:

• For a factory restoration, use OEM-quality parts from brands like Moog (Problem Solver line), AC Delco, or Raybestos. These keep the car authentic and perform as original, with rubber bushings and standard rates.
• For a street performance build, mix and match: stock springs with gas shocks and poly bushings work well. Or go for adjustable shocks and aftermarket springs.
• For a track/autocross build, invest in coilovers, tubular arms, and adjustable sway bars. Expect a firmer ride.

Brake-Upgrade Interrelationships

Suspension upgrades often require brake upgrades to keep the car balanced. The 79 Trans Am used disc brakes up front and drums in the rear. If you plan to increase power or drive aggressively, consider upgrading to larger rotors and multi-piston calipers (like from a later F-body or aftermarket kits). Better suspension puts more demand on brakes.

Practical Tips for Buying 79 Trans Am Suspension Parts

1. Measure before you buy. Many parts depend on ride height and options (WS6 vs standard suspension). The WS6 package had thicker sway bars and different spring rates. Measure your current components or look up RPO codes.
2. Check compatibility. Parts from 1979-1981 Trans Am and Firebird are generally interchangeable, but verify year-to-year differences (e.g., lower control arm bushings changed).
3. Look for complete kits. Some manufacturers (like UMI Performance, Hotchkis, and BMR) offer full suspension kits that ensure parts work together. This saves time and avoids mismatched rates.
4. Don't skimp on bushings. While rubber is original, polyurethane lasts longer and tightens up handling. If you want a quiet daily driver, stick with rubber.
5. Consider weight reduction. If you've removed heavy items (like A/C, smog pumps), you may need different spring rates to maintain proper ride height.
6. Align after installation. Any suspension changes—especially control arms, springs, or tie rods—require a professional alignment to prevent tire wear and ensure safe handling.

Common Mistakes to Avoid

• Buying based on price alone. Cheap shocks and springs often fail quickly.
• Mixing spring rates front and rear. If you lower the front with 1-inch drop springs but leave the rear stock, the car will look nose-down and handle poorly.
• Ignoring the steering box. A worn box hides the benefits of new suspension.
• Not replacing hardware. Bolts, nuts, and washers are cheap; reuse at your own risk.

Final Recommendation

For most 79 Trans Am owners, the best upgrade path starts with replacing all worn rubber with Moog Problem Solver components (ball joints, tie rods, bushings) and upgrading to KYB Gas-A-Just shocks on all four corners. Add a set of polyurethane sway bar bushings and new tie rod ends. This keeps costs down while restoring crisp handling. If you want noticeable improvement without altering ride height, pair the shocks with stock-replacement springs from Moog or Eaton. For those with a larger budget and a desire for adjustability, QA1 single-adjustable coilovers up front and Viking double-adjustable shocks out back combined with dropped leaf springs from Eaton will give you a car that handles far beyond stock—perfect for spirited driving or occasional track use.

Always consult your suspension and alignment specifications before purchasing, and if in doubt, reach out to a specialist vendor who knows these cars. The right parts will make your 79 Trans Am drive like a modern performance machine while respecting its classic roots.