Freightliner FLC120 Leaf Springs, Hangers & Acc.

Frequently Asked Questions About Freightliner FLC120 Leaf Springs, Hangers & Acc.

Will these leaf springs fit my specific year FLC120, and what are the weight capacity differences?

Freightliner FLC120 leaf springs are generally compatible across model years 1987-1999, but there are important variations. The standard 3-leaf spring pack handles up to 12,000 lbs, while the heavy-duty 4-leaf configuration supports 14,000-16,000 lbs. Always verify your truck's VIN and front axle weight rating (FAWR) before ordering. Pre-1990 models may have different mounting hole patterns on the hangers, requiring specific part numbers.

What tools and equipment do I need to replace leaf springs and hangers myself?

You'll need a heavy-duty floor jack (minimum 20-ton capacity), jack stands rated for commercial trucks, impact wrench with deep sockets (typically 15/16" and 1-1/8"), spring compressor or C-clamps, penetrating oil, and a torque wrench capable of 250-350 ft-lbs. The job typically takes 4-6 hours per side. Many customers report needing to heat seized bolts with a torch, especially on older trucks. Professional installation runs $400-600 per axle if you prefer to avoid the heavy lifting.

How can I tell if I need standard or heavy-duty leaf springs, and what's the difference in ride quality?

Check your door jamb sticker for GAWR (Gross Axle Weight Rating). Standard springs work for trucks under 12,000 lbs front axle weight, while heavy-duty is needed above that. Heavy-duty springs use thicker steel (typically 3/8" vs 5/16") and may include an additional leaf. Standard springs provide a smoother empty ride but can sag under heavy loads. Heavy-duty springs ride stiffer when empty but maintain proper height and handling when loaded. Many owner-operators choose heavy-duty for versatility.

What's included in a complete leaf spring kit, and what additional parts might I need?

A complete kit typically includes the leaf spring pack, center bolt, and U-bolts. However, you'll often need to purchase separately: shackle bushings ($25-40 per set), shackle pins ($30-50), spring eye bushings ($20-30 each), and new hangers if yours are cracked or worn ($75-150 each). Anti-squeak pads between leaves are recommended ($15-25). Many customers find their 20+ year old hangers have stress cracks once removed, so budget for potential hanger replacement.

How long do aftermarket leaf springs typically last compared to OEM, and what brands are most reliable?

Quality aftermarket springs from established manufacturers like Dayton Parts, Triangle Suspension, and Hendrickson typically last 150,000-250,000 miles with proper maintenance, compared to 200,000-300,000 for OEM. The key difference is steel quality and heat treatment. Look for springs made from 5160H steel alloy with shot-peened finish for longevity. Avoid no-name imports that may use inferior steel and lack proper arch. Regular greasing of bushings and checking U-bolt torque every 25,000 miles significantly extends lifespan regardless of brand.