Complete Guide to Front Suspension Parts for a 1999 GMC Sierra

If you own a 1999 GMC Sierra, maintaining the front suspension is critical for safe handling, tire wear, and ride quality. Over two decades of service, rubber bushings dry out, ball joints develop play, and shocks lose their damping ability. This guide covers the key front suspension parts you may need to replace, along with practical advice on choosing between OEM and aftermarket options.

Key Front Suspension Components for the 1999 GMC Sierra

The front suspension on the 1999 Sierra is a double-wishbone design with torsion bars. Understanding each component helps you diagnose problems and plan repairs.

Upper and Lower Control Arms

Control arms connect the wheel hub to the frame and allow vertical movement. The 1999 Sierra uses stamped steel control arms with replaceable ball joints and bushings. If the control arm itself is bent or rusted, replace the entire assembly. Otherwise, you can press in new bushings and ball joints. Pro tip: Moog and AC Delco offer quality control arms with pre-installed ball joints and bushings.

Ball Joints

Ball joints are the pivot points between the control arms and the steering knuckle. Worn ball joints cause clunking noises, uneven tire wear, and vague steering. For a 1999 Sierra, you need both upper and lower ball joints. Lower ball joints typically wear faster because they carry more load. Replace in pairs (both sides) and consider doing all four at once.

Tie Rod Ends

Tie rod ends connect the steering rack to the wheel hub. Loose tie rods create steering wander and play. The 1999 Sierra has inner and outer tie rod ends on each side. Always replace them in pairs or as a complete set. After removing the old parts, get a professional alignment.

Sway Bar Links

The sway bar (stabilizer bar) reduces body roll. Sway bar links connect the bar to the control arms. Worn links cause clunking over bumps and swaying in corners. These are inexpensive and easy to replace—plan on doing them every 50,000 miles.

Bushings

Bushings are rubber or polyurethane cushions that isolate vibration. Key bushings include control arm bushings, sway bar bushings, and strut rod bushings (if equipped). Worn bushings cause alignment shifts and noises. Polyurethane bushings last longer but transmit more road feel.

Shocks and Struts

The 1999 Sierra uses twin-tube shock absorbers in the front (no struts). Shocks control spring oscillation and damping. Replace them if you notice excessive bounce, nose dive under braking, or fluid leaks. Gas-charged shocks like Bilstein or Monroe offer better performance.

OEM vs Aftermarket Parts: What to Consider

Parts for the 1999 GMC Sierra fall into three categories:

• OEM (AC Delco): Direct fit, same quality as original. More expensive but guaranteed fit and performance.
• Premium Aftermarket (Moog, Raybestos, Mevotech): Often improved over OEM with stronger materials, greasable ball joints, and hardened bushings. Many DIYers prefer Moog for its extended grease zerks.
• Budget Aftermarket (Duralast, Detroit Axle): Lower price but may use softer bushings and seals. Suitable for a daily driver if you replace often.

Advice: For critical safety parts like ball joints and tie rods, stick with OEM or premium aftermarket. For bushings and sway bar links, budget parts are acceptable.

Recommended Brands and Quality Levels

Best Overall: Moog – their "Problem Solver" line includes features like double-boot seals and steel sleeves that resist corrosion. OEM Equivalent: AC Delco – exact fit, but some parts may lack grease fittings. Performance: Bilstein – if you upgrade shocks, their 4600 series provides excellent stability. Budget Pick: Detroit Axle – complete front suspension kits under $200, but expect to replace bushings sooner.

Replacement Tips for DIYers and Shops

1. Inspect the torsion bars: The 1999 Sierra uses torsion bars for ride height. If you change control arms, loosen the torsion bar adjusters to relieve tension before disassembly.
2. Use penetrating oil: Spray bolts and nuts a day ahead. Rust is common on older trucks.
3. Replace hardware: Many kits include new nuts and bolts. If not, buy them separately—they are torque-to-yield in some cases.
4. Get an alignment: Any suspension work involving control arms or tie rods requires a four-wheel alignment.
5. Consider a complete kit: Companies like Mevotech and Moog sell front suspension kits that include everything. This saves time and ensures all parts are fresh.

Final Recommendation: Building a Complete Front Suspension Kit

For a 1999 GMC Sierra with over 150,000 miles, a full front suspension rebuild is worthwhile. I recommend this package:

• Lower and upper control arms with ball joints (Moog or AC Delco)
• Inner and outer tie rod ends (Moog)
• Sway bar links (Moog or Mevotech)
• Shocks (Bilstein 4600 or Monroe OE Spectrum)
• Polyurethane control arm bushings if you want longevity

This combination balances cost, durability, and ride quality. If you are on a tight budget, replace only the lower ball joints, outer tie rods, and shocks. But tackling the full job now avoids returning to the same corner of the truck later.

Remember to torque all fasteners to factory specifications. A service manual for the 1999 Sierra is essential for bolt torque values and procedure. With the right parts and patience, your Sierra will drive like new again.