2016 Kenworth T680 — Wheel Alignment Specifications

Quick reference

Note: Exact numeric specifications must be taken from Kenworth/PACCAR OEM service information for the 2016 T680 configured with your specific steer axle and rear suspension (e.g., AG380, AG400L, AG460, etc.). Do not substitute generic heavy‑truck values.

Adjustability

Front (steer axle):

• Toe: Factory adjustable at the tie‑rod sleeve. This is the primary front alignment adjustment on the T680.
• Caster: Not directly adjustable via an eccentric from the factory. Caster is set by axle/spring geometry and is adjusted by installing steel caster wedges (shims) between the axle pad and the leaf spring, or by repositioning/realigning spring packs. Always loosen/retorque U‑bolts to spec after wedge changes.
• Camber: Not factory adjustable. Camber is established by the I‑beam axle forging. Correction, when needed, is typically performed by a heavy‑duty alignment shop using controlled axle bending per OEM guidance, or by axle replacement if out of spec or damaged.
• SAI: Not adjustable. Used as a diagnostic angle to assess bent components (axle beam, knuckles, or kingpins).

Rear (drive/tandem axles):

• Thrust angle and axle skew: Adjustable depending on rear suspension. On common Kenworth AG‑series air suspensions, axle alignment is set by adjusting torque rods/track bars or eccentric hardware at the hanger/trailing arm bushings. Some suspensions use shim packs at the hanger brackets. Objective is to set both drive axles parallel to each other and square to the chassis centerline.
• Rear toe (individual wheel): Not independently adjustable per wheel; toe changes with axle skew. The alignment procedure sets each drive axle so that individual wheel toe falls within OEM tolerance when axles are square/parallel.
• Camber/caster (rear): Not adjustable. Measured only to verify axle or housing integrity.

Because the T680 could be ordered with multiple steer axles and rear suspensions, always follow the exact adjustment process in the Kenworth/PACCAR service manual and in the suspension manufacturer’s documentation (e.g., AG380/AG400L/AG460 procedures) for torque values and adjustment points.

Recommended adjustment hardware

• Tie‑rod sleeve tools and new clamps: For precise front toe adjustment; replace damaged/rounded clamps.
• Caster wedges (steel shims), 1–4° assortment: For setting front caster when OEM allows shim correction. Use new U‑bolts and nuts when required by procedure.
• Heavy‑duty axle camber correction (professional axle bending): Only by qualified HD alignment shops and within OEM limits. Do not use improvised heat methods.
• Adjustable torque rods/track rods or eccentric bushing kits: For setting rear axle thrust and parallelism on AG‑series and other common HD air suspensions. Use components approved for your suspension (Kenworth/PACCAR, Meritor, Hendrickson, ATRO, etc.).
• Hanger/shackle shim kits and replacement hardware: Where the suspension design specifies shimming at the brackets to correct axle skew.

Always replace worn bushings and torque all fasteners to OEM specs after adjustment. Air suspension ride height must be set and verified before any alignment.

Symptoms of bad alignment

• Steer tire feathering: Alternating high/low tread ribs when you slide your hand across the tread, commonly caused by incorrect toe.
• One‑shoulder steer tire wear: Excessive inner or outer shoulder wear can indicate camber or caster split issues, bent axle/knuckle, or prolonged toe error.
• River wear/erosion on steer tires: Wavy wear patterns near the shoulder, often associated with toe and compliance issues.
• Pull or drift and off‑center steering wheel: May result from caster split, thrust angle error, or unequal tire pressures. Verify chassis cross‑weights and brake drag as well.
• Dog‑tracking: Vehicle appears to travel slightly sideways; typically caused by incorrect thrust angle from misaligned drive axles.
• Drive axle heel‑and‑toe wear or rapid shoulder wear: Indicates axle skew, incorrect thrust/parallelism, or bushing compliance in the suspension.

When to align

• After installing steer or drive tires or performing tire rotations.
• After any steering or suspension work (kingpins, tie‑rod ends, spring packs, torque rods, bushings, airbags, hangers, shocks).
• After impact (pothole, curb, collision) or off‑road events.
• When ride height is corrected or air suspension components are replaced.
• At regular intervals: Many fleets inspect alignment at 50,000–100,000 miles or annually, depending on operating conditions.

Always set tire pressures to fleet/OEM targets and verify ride height before alignment. Inspect for worn bushings, loose U‑bolts, and wheel bearings/kingpins prior to measurements.

Typical alignment cost

• Steer‑axle (front) alignment only: Commonly $150–$250 in many markets.
• Three‑axle (tractor) alignment: Commonly $250–$450 depending on region and suspension.
• Additional camber correction (axle bend) or caster wedge installation: Extra labor and materials; shops may quote $150–$300+ for axle correction and parts as needed.

Pricing varies by region and condition of components. Worn bushings, seized sleeves, or required hardware replacement will add cost.

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