Suspension And
Steering Repair

King pin wear is one of the most critical steer axle issues on Class 8 trucks and a frequent DOT out-of-service item. We measure king pin lateral play using a dial indicator at the wheel with the vehicle loaded — identifying wear that visual inspection alone cannot confirm. King pins and bushings are replaced as a complete set to restore steering precision.

Following king pin replacement, the steer axle is inspected for steering knuckle wear, tie rod end condition, and front axle beam straightness. A bent or twisted axle beam produces alignment issues that king pin replacement alone will not resolve — we verify the complete front end geometry before the alignment is performed.

• Replacement to OEM specification king pins and bushings
• Steering knuckle and thrust bearing inspected with every king pin job
• Post-installation alignment performed to verify correct caster and toe

Leaf spring inspection covers all leaves for cracks, center bolt condition, U-bolt torque, and spring eye bushing wear. A broken leaf spring often goes unnoticed until the truck develops a visible lean or irregular tire wear pattern. We inspect all spring packs during routine service intervals to catch fatigue cracks before they cause a failure.

Spring hanger inspection covers all mounting brackets for cracks, elongated bolt holes, and frame rail damage at the hanger attachment points. Cracked hangers transfer stress into the frame rail and accelerate frame damage. We replace hangers and repair frame-mount areas before damage progresses to a structural repair.

• U-bolt replacement and torque to specification with every spring job
• Spring eye bushings replaced when wear exceeds service limits
• Load test performed after spring assembly to verify correct ride height

Air bag suspension diagnosis begins with a ride height inspection under load and a system pressure test. Height control valve operation is tested to confirm the valve responds correctly to frame position changes and holds correct ride height at all load conditions. Failed height control valves are a frequent cause of uneven bag pressure and premature bag wear.

Air bag replacement covers both the bag assembly and the mounting hardware. Worn or cracked bag pistons are replaced along with the bag itself, as a new bag on a damaged piston will fail prematurely. All air supply lines to the bags are inspected for chafe and fitting condition before the system is pressurized and road tested.

• Ride height verified with truck loaded to operating weight
• Air supply lines and fittings replaced if chafe or corrosion is found
• Shock absorber condition assessed with every air bag inspection

Steering gear inspection covers free play measurement, sector shaft adjustment, and hydraulic leak assessment at all seals and fittings. Excess free play at the steering wheel — typically more than two inches measured at the rim — indicates gear wear or incorrect adjustment that compromises driver control and directional stability.

Pitman arm, drag link, and tie rod inspection covers worn ball joints, loose clamp connections, and bent components. A worn drag link ball joint is a common cause of steering wander that is frequently misdiagnosed as a tire or alignment issue. We inspect all steering linkage before and after alignment to verify every joint is within specification.

• Power steering pump flow and pressure tested with every gear job
• Hydraulic fluid condition and reservoir level inspected and corrected
• All steering joints lubricated and confirmed accepting grease

Commercial truck alignment covers steer axle toe, caster, camber, and axle centerline to frame. We perform alignment with the truck at operating weight using calibrated alignment equipment to ensure the setup reflects actual road conditions. Alignment performed on an empty truck can produce incorrect results on a loaded vehicle.

Drive axle alignment — setting the rear axle perpendicular to the frame centerline — is performed alongside steer axle alignment to correct trailer pull and diagonal tire wear on the drive position. A misaligned rear axle causes steer tires to work against the direction of travel, accelerating both tire and front-end component wear.

• Tandem axle parallelism checked and corrected when out of specification
• Tire wear pattern analyzed before and after alignment
• Alignment printout provided with before and after measurements

Wheel end inspection covers bearing endplay measurement, hub oil level and condition, seal integrity, and spindle nut torque. Bearing endplay outside of specification causes irregular tire wear, brake drum runout, and ABS sensor signal interference. We measure and set bearing endplay to manufacturer specification on every hub service.

Hub oil and grease services are performed on a mileage basis as part of a structured PM program. Contaminated hub oil — appearing milky or containing metallic particles — indicates a failed inner seal allowing water or brake drum material to enter the hub. Contaminated hubs are drained, inspected for bearing damage, and resealed before refilling.

• Spindle nut torque verified with a calibrated torque wrench
• Outer seal installed and confirmed seated before wheel is reinstalled
• Wheel stud condition and thread length inspected with every hub jobf