This commercial driver study guide covers relevant Federal Motor Carrier Safety Administration (FMCSA) Entry-Level Driver Training (ELDT) concepts and California commercial driver knowledge topics. Review the regulations, procedures, and safety checklists below as part of your CDL and commercial learner permit (CLP) preparation.
Suspension components
Inspect springs, leaves, air bags, hangers, shackles, torque arms, radius rods, U-bolts, shocks, and axle mounts as equipped. Look for cracks, displacement, missing parts, leaks, looseness, and contact with other components.
Brake components
Inspect hoses/lines, chambers or calipers, pushrods/slack adjusters where applicable, drums/rotors, and linings/pads. Check mounting, damage, contamination, leakage, and adjustment using the applicable standard.
Wheels and rims
Check rims for cracks, bends, unauthorized welds, elongated holes, and damage. Inspect all lug nuts for tightness clues such as rust trails, shiny threads, or missing fasteners. Mismatched or damaged wheels require service.
Hubs and seals
Check hub oil level where visible, axle seals, bearing areas, and wheel surfaces for leakage. Oil on a tire or brake can indicate seal failure and loss of braking friction.
Tires
Inspect inflation, tread depth using current axle-specific minimums, cuts, bulges, exposed cord, sidewall damage, valve stems, objects, and proper matching. Dual tires must not touch and must be free of trapped debris.
Repeat every axle
Do not describe one wheel and assume all others match. The test may require representative or complete inspection according to current rules, but safe operation requires every axle and tire to be serviceable.
Scenario
A drive-wheel lug nut has a fresh rust trail. The applicant identifies possible looseness and does not dismiss it because the remaining nuts appear tight.
Commercial Driver License Exam Readiness: Achieving a passing grade of 80% or higher on state DMV commercial driver knowledge exams requires mastery of federal vehicle inspection procedures, gross vehicle weight ratings (GVWR / GCWR), braking mechanics, and road safety regulations.