Frequently Asked Questions About Freightliner FLC120 Steer Axle Springs & Hangers

Will these springs and hangers fit my specific year FLC120, and are there differences between model years?

Freightliner FLC120 steer axle springs and hangers are generally compatible across model years from 1988 to 2003, but there are important variations. The main differences occur between pre-1995 and post-1995 models, particularly in the hanger bracket mounting hole patterns and spring eye dimensions. Always verify your truck's specific configuration by checking the spring pack code on your existing springs (usually stamped on the main leaf) or measuring the spring length from center of eye to center of eye. Most FLC120s use either a 26-inch or 28-inch spring length for the steer axle.

What weight capacity springs should I choose for my application?

The correct spring capacity depends on your typical front axle loading. Standard FLC120 steer axle springs range from 12,000 to 14,600 pounds capacity. For highway tractors, 12,000-pound springs typically suffice. For vocational trucks, heavy-haul applications, or those with heavy front-mounted equipment, consider 13,200 or 14,600-pound rated springs. Remember that springs should be replaced in pairs to maintain proper ride height and handling. Overloading springs beyond their rating causes premature wear and dangerous handling characteristics.

Can I replace just the springs without changing the hangers, or should both be done together?

While springs can technically be replaced without changing hangers, it's strongly recommended to inspect hangers whenever replacing springs. Look for cracks around the spring pin holes, elongated pin holes, or bent hanger brackets. If hangers show any wear, replace them simultaneously to avoid premature spring failure. The labor cost difference is minimal when doing both, and worn hangers will quickly damage new springs. Additionally, new hanger bushings should always be installed with new springs to ensure proper articulation and prevent binding.

What tools and equipment do I need for installation, and how difficult is this job?

Installing steer axle springs requires proper equipment including a heavy-duty floor jack (minimum 20-ton capacity), jack stands rated for commercial trucks, spring compressors or C-clamps, and a torque wrench capable of 450-500 ft-lbs. You'll also need basic hand tools and potentially a torch for removing seized pins. This is an intermediate to advanced job requiring 4-6 hours for experienced mechanics. The truck must be properly supported with the frame rails level. Critical torque specifications include spring U-bolts (450-500 ft-lbs) and hanger bolts (250-300 ft-lbs). Many drivers choose professional installation due to safety concerns and the need for proper alignment afterward.

What's the difference between OEM-style and heavy-duty aftermarket springs?

OEM-style springs match factory specifications using standard carbon steel with typical paint finishes. Heavy-duty aftermarket options often feature upgraded materials like chrome-silicon steel, which provides 20-30% longer service life under heavy use. Aftermarket springs may also offer improved corrosion resistance through powder coating or galvanizing versus standard paint. Some aftermarket manufacturers provide progressive-rate springs that offer better empty ride quality while maintaining full load capacity. Price differences typically range from 15-25% more for heavy-duty options, but the extended service life often justifies the cost for high-mileage operations.