FMCSR 393.47(f) — Brake Actuators Defective: Driver FAQ

No. Across our 13 million inspection records, the 351 citations for defective brake actuators or chambers show a 0.0% out-of-service rate—meaning no trucks were placed OOS for this violation. This makes 393.47(f) significantly less severe than the all-FMCSR average of 31.4% OOS rate. However, do not mistake this for permission to delay repair. The violation is still documented and carries CSA weight.

This violation carries a CSA severity weight of 7. The actual points on your record depend on the 30-day point multiplier applied by your state. In a 30-day window, you can accumulate multiple violations that all add up. One 393.47(f) citation with a severity weight of 7 will be entered into your carrier's Safety Management Cycle data; stacking multiple violations across 30 days increases your CSA Unsafe Driving or Mechanical BASIC score.

Immediate steps: (1) Have the brake actuator, chamber, or related component inspected by a certified mechanic—do not defer this. (2) Document the inspection and any repairs in writing. (3) Review the inspector's findings for accuracy; if components were cited as defective but are actually in spec, prepare documentation to contest via FMCSA DataQs. (4) Notify your fleet manager or carrier if you're not owner-op. (5) Request a re-inspection after repair to clear the violation from your record.

Moderately serious, but far lower OOS risk than peer codes. Our data shows 393.47(f) ranks #1033 out of 3,036 FMCSR codes by citation volume—not in the top tier. More telling: its 0.0% OOS rate contrasts sharply with 393.47E (slack adjuster defective, 0.0% OOS) but is much better than peer code 396.3(a)(1) general maintenance violations at 45.3% OOS. The violation is noted but statistically less likely to strand your truck than other brake system issues.

Yes, if you have evidence. DataQs allows drivers and carriers to contest inspection records through FMCSA's Request for Data Review. If the inspector cited brake components as defective but your maintenance records or a subsequent inspection show they're in spec, submit documentation (inspection reports, photos, service logs) proving the components meet FMCSR standards. Equipment-based violations like this are contestable if you can prove the inspector erred in judgment or the components were actually compliant.

Relatively uncommon. Our inspection database contains 351 all-time citations for 393.47(f) brake actuator defects. Notably, there have been zero citations in the last 12 months and zero in the last 90 days, indicating this violation is becoming rarer. For context, the most-cited vehicle maintenance code (393.9(a) inoperable lamps) has 660,737 citations—meaning brake actuator defects account for less than 0.1% of vehicle maintenance violations.

Freightliner is the most-cited make. Across our records, FRHT has 43 citations for defective brake actuators, followed by FREIGHTLIN with 36, KENWORTH with 22, and VOLVO with 20. This may reflect market share—Freightliner is a high-volume truck manufacturer—rather than inherent mechanical problems. The spread suggests brake actuator defects occur across multiple manufacturers and are not concentrated in one brand.

Both. The citation is filed under your carrier's USDOT number and appears in the carrier's CSA Safety Management Cycle, which affects the company's Mechanical BASIC score. However, inspection records are also tracked under the individual unit's VIN and the driver's history. Your carrier uses this data for internal safety ratings, but the primary CSA compliance effect is on the carrier, not a personal driving record like your CDL status.