FMCSR 393.47: Brake Actuators/Chambers Defective — Q&A

No. Across our inspection database, 393.47 citations have never resulted in an out-of-service placement. The OOS rate for this violation is 0.0%, meaning inspectors cite the defect but allow continued operation. However, this does not mean the brake components are safe to leave unrepaired—it reflects current enforcement practice, not regulatory permission to operate with defective brakes.

A single 393.47 citation carries a CSA severity weight of 7 points. In the 30-day rolling CSA safety rating window, this violation is weighted at 7 points per occurrence. The total impact on your BASIC score depends on how many violations you accumulate within that 30-day period and their individual severity weights.

1. Document the citation details: Get a copy of the inspection report and note the specific brake component(s) cited as defective.
2. Schedule repair immediately: Contact your carrier's maintenance or your own mechanic—do not defer this work.
3. Verify root cause: Determine whether the defect is in the actuator, chamber, linkage, or another component so the repair addresses the actual problem.
4. Request re-inspection (if applicable): Once repaired, you may request a follow-up inspection to clear the violation from active records.
5. Review your pre-trip inspections: Ensure your daily brake checks are catching wear early.

Compared to similar Vehicle Maintenance codes, 393.47 is cited far less frequently than peer violations. For example, slack adjuster defects (393.47E) account for 180,363 all-time citations, while inoperable lamps (393.9) have 660,737 citations. However, the 0.0% OOS rate for 393.47 contrasts sharply with 396.3(a)(1) (general inspection/repair/maintenance), which has a 45.3% OOS rate. Brake defects are taken seriously during inspection, but this specific code rarely triggers immediate removal from service.

Yes. The FMCSA DataQs (Inspection/Out-of-Service Records Dispute) process allows you to challenge roadside inspection findings through your carrier or directly if you're an owner-operator. For equipment defects like brake actuators, contestation typically requires documented evidence of repair, maintenance records, or proof that the component met specification at the time of inspection. File your dispute within the regulatory timeline through your carrier's safety office or FMCSA's DataQs portal.

Immediately urgent. Brake actuator or chamber defects compromise stopping power and create safety risk. Even though the 0.0% OOS rate means you were not placed out of service, the violation signals that inspectors found a malfunction—not merely wear. Delaying repair increases your liability if you're involved in an accident, and a repeat inspection on the same component could result in a more severe enforcement action. Repair before your next significant movement.

Our inspection records show zero citations for 393.47 across all time periods (all-time, last 12 months, and last 90 days). This indicates the violation is either extremely rare in enforcement practice or defined so narrowly that inspectors cite related codes (such as 393.47E for slack adjuster defects, which has 180,363 citations) instead. If you receive a 393.47 citation, treat it as noteworthy—it is not a routine finding in our database.

FMCSA safety violations are recorded against the carrier's operating authority and safety record, not permanently against individual drivers. However, the citation and associated CSA points remain part of the inspection record and may affect future carrier hiring decisions if prospective employers review your inspection history. Your current carrier's safety metrics are impacted, which can influence their insurance costs and regulatory oversight. Work with your carrier to resolve the defect and prevent repeat citations.