SPRINGS

Springs For Peterbilt Trucks

Leaf springs and coil springs support the static and dynamic load of a Peterbilt truck and its cargo, maintaining ride height and controlling axle movement under braking, acceleration, and cornering forces. On Class 8 trucks, front axle leaf springs are the most common configuration, while rear suspensions range from multi-leaf spring packs to air ride systems depending on the application. Broken, sagged, or cracked spring leaves compromise load capacity, handling, and ride quality. We carry replacement springs and spring components for Peterbilt trucks across steer and drive axle configurations.

Frequently asked questions about springs

How do I know if a leaf spring is broken on a Peterbilt?

A broken leaf is often visible as a misaligned or offset section in the spring pack when viewed from the side, or as a visible crack or gap between leaves. The truck may sit lower on the affected corner, and the spring eye or center bolt area may show displacement. On the steer axle, a broken spring leaf can also cause the axle to shift forward or rearward relative to the spring perch, creating a caster angle change that produces steering pull. Any broken leaf in a spring pack is cause for immediate replacement — running on a broken spring risks complete spring failure and loss of vehicle control.

Can I replace individual leaves in a spring pack, or does the whole pack need to come out?

Individual leaf replacement is possible but requires removing the spring pack from the truck to safely disassemble and reassemble it — spring packs are held under significant pre-load tension that makes field disassembly without proper tooling dangerous. Most shops replace the entire spring pack as an assembly rather than individual leaves, as the labor difference is modest and a complete new pack ensures all leaves are matched in temper and thickness for consistent load distribution.

What causes leaf springs to sag or lose their arch on a Peterbilt?

Spring sag is caused by metal fatigue from repeated load cycles over high mileage, chronic overloading beyond the spring's rated capacity, or heat damage from proximity to exhaust components. Springs that have lost their arch reduce ride height, change the suspension geometry, and reduce the effective load capacity of the axle. A truck that sits noticeably lower on one side than the other, or that rides at reduced height on a lightly loaded axle, likely has sagged springs that need replacement.

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