Practical Skills and Training Flashcards

During a front-end alignment on a truck, caster angle is found to be unequal side-to-side. The MOST common adjustable correction method involves:

Answer: Adding or removing shims at the axle seat or adjusting eccentric bolts

Caster is corrected by shimming the axle spring seats to change the axle's tilt angle fore-and-aft, or by adjusting eccentric cam bolts on vehicles with radius arm suspensions.

A coach equipped with an air-ride rear suspension shows one side riding lower than the other with the leveling valve functioning normally. The MOST likely cause is:

Answer: A failed or leaking air spring on the low side

If the leveling valve is functioning but one side stays low, the air spring on that side is likely leaking or has an internal failure preventing it from holding pressure.

When measuring kingpin inclination (KPI) and camber together, the sum of these angles is used to determine:

Answer: Included angle

The included angle equals KPI plus camber; this value helps diagnose bent steering knuckles or axles because it remains constant even when camber changes from a bent part.

A technician is checking driveshaft phasing on a truck. Correct phasing means:

Answer: The yokes at both ends of the shaft are aligned in the same plane

Proper phasing requires the front and rear yokes to be in the same rotational plane so the velocity variation created by one U-joint is cancelled by the other.

When performing a steer axle wheel bearing adjustment on a truck using the standard procedure, after hand-tight the bearing nut is torqued to seat the bearings, then backed off and:

Answer: Finger-tightened and locked with a cotter pin or lock ring

After seating and backing off, the bearing nut is hand-tightened to achieve slight end play, then secured with a cotter pin or lock ring per manufacturer's specification.

A technician suspects a leaking axle shaft seal on a drive axle. Before removing the axle shaft, the FIRST step is to:

Answer: Mark the axle shaft flange position relative to the hub

Marking the axle shaft flange to the hub before removal ensures the shaft is reinstalled in the same rotational position, preserving balance and preventing stress on the axle splines.

During a transmission fluid analysis on an Allison automatic, the fluid appears dark brown with a burnt smell but no metal particles. This MOST likely indicates:

Answer: Clutch pack slippage and heat degradation

Dark, burnt-smelling fluid with no metallic debris typically points to clutch pack slippage generating excessive heat, which darkens and degrades the fluid without producing large metal particles initially.