Prior to departing on a route, a driver inspects the wheel-end air brake hardware and air lines across all axles. Which of the following findings constitutes a serious mechanical defect that requires the vehicle to be taken out of service?
- A brake drum exhibiting a through-crack that extends across more than half the width of the friction surfaceCevap
- BA manual slack adjuster showing 3/4 inch of pushrod travel when pulled firmly by hand with the parking brake released
- CA drum brake lining thickness measuring 3/8 inch with no oil or grease contamination
- DA brake chamber pushrod angle relative to the slack adjuster arm measuring slightly greater than 90 degrees when released
Cevap
A brake drum exhibiting a through-crack that extends across more than half the width of the friction surface constitutes an immediate out-of-service defect.
Commercial driver vehicle inspection standards state that brake drums or rotors must not have cracks extending through the drum or across more than half the width of the friction surface. Such cracks compromise braking capability and risk total drum failure, requiring the vehicle to be placed out of service immediately.
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Anahtar Kavram
Brake System Components Inspection Thresholds and Out-of-Service Criteria
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