Leaf Spring

What leaf springs do

A leaf spring is a stack of curved steel leaves, bolted to the axle and mounted to the frame at each end. It supports the load, locates the axle and controls how the axle moves. Because leaf springs are both the spring and a locating link, they strongly influence ride quality, load capacity and handling. They sag over time, especially on trucks that haul or tow, and a tired spring is a common reason for a drooping rear end or a sloppy feel.

Types of replacement springs

• OE replacement springs: restore original ride height and capacity for a worn vehicle.
• Softride or comfort-tuned springs: use fewer leaves or a different curve for a smoother ride at a rated load.
• Lift springs: built with extra arch for added height, in listings such as 3, 4, 5 or 8 inches, often for specific vehicles.
• Flex-oriented springs: engineered for added articulation on trail vehicles.

What to compare

• Position: front or rear, and driver or passenger side if indicated.
• Spring quantity: some listings are single springs, while others are sold as a pair or a kit.
• Bushings: rubber is quieter, polyurethane is firmer. Check whether bushings are included, and whether the eye diameter matches your hardware.
• Lift and rate: the lift number depends on load, so a loaded truck sits lower than an empty one. Confirm the spring rate suits your payload.

Fitment

Leaf springs are vehicle specific. Axle width, eye size, spring perch and frame mounting differ between model years, cab and bed configurations, and between front and rear. Confirm fitment for your exact year, make and model, and review the maker's specifications on lift height, shackle length and recommended accessories.

Installation notes

Lifting a vehicle changes steering, brake line, driveshaft and shock requirements. Longer shocks, brake lines, shackles or driveshaft angle corrections may be needed. Support the frame on rated jack stands, never rely on a jack alone, and torque U-bolts and shackle bolts to the specified values after the vehicle is sitting at ride height. Re-torque after a short drive. Because springs are a safety part, professional installation and an alignment are recommended.

Replace springs in axle pairs so that both sides sit at the same height.

Inspection and common mistakes

Leaf springs usually give warning before failing. Look for a cracked main leaf, shifted leaves, worn wear pads, a loose center bolt and rust between leaves. Sagging can be measured by comparing the distance from the axle to the frame side to side.

• Do not ignore U-bolts. They stretch under load. New U-bolts are typically recommended whenever springs are replaced, and they should be torqued in a crisscross pattern.
• Check the shackles and hangers. Worn shackle bushings and cracked hangers can cause rear-end wander even with new springs.
• Consider a add-a-leaf only as a stopgap. It can restore some height or capacity, but it will not fix a worn spring pack.
• Watch axle wrap. Lifted or high-torque vehicles may need traction bars or similar parts to control axle wrap under hard acceleration.
• Allow time to settle. New springs often settle in the first weeks, so check height afterward.