393.53 Violation: What It Means and How to Fix It
Data through September 24, 2026 · Last updated October 28, 2026 · By Chad Griffith, founder
Quick Answer
393.53 (Automatic brake adjusters and brake adjustment indicators) was cited 30,393 times in roadside inspections of interstate for-hire carriers with 5 to 50 trucks from September 25, 2024 to September 24, 2026, and 0.0% of those citations put the driver or vehicle out of service. The most common version is 393.53B-B: Air Brake - CMV manufactured on or after 10/20/1994 has an automatic airbrake adjustment system that fails to compensate for wear.
30,393
Citations on carriers with 5 to 50 trucks
0%
Out of service
143,960
All carriers, same period
What the rule says
Air-braked vehicles built on or after October 20, 1994 must have working automatic brake adjusters and adjustment indicators (49 CFR 393.53).
When it puts you out of service
Not out of service by itself here, but a failed adjuster leads to brakes out of adjustment and, on enough brakes, out of service.
The codes on the inspection report
| Code | What the officer wrote | Severity weight | Citations, 5 to 50 trucks | Out of service |
|---|---|---|---|---|
| 393.53B-B | “Air Brake - CMV manufactured on or after 10/20/1994 has an automatic airbrake adjustment system that fails to compensate for wear” | 4 | 22,126 | 0.0% |
| 393.53B | “CMV manufactured after 10/19/94 has an automatic airbrake adjustment system that fails to compensate for wear” | 4 | 7,620 | 0.0% |
| 393.53BMAN | “Air Brake - CMV manufactured on or after 10/20/1994 is not equipped with automatic air brake adjusters” | 4 | 499 | 0.0% |
| 393.53C-B | “Air Brake - No brake adjustment indicator manufactured on or after October 20 1994” | 4 | 124 | 0.8% |
| 393.53C | “No or Defective Brake Adjustment Indicator on Air Brake System for vehicle manufactured after 10/19/1994” | 4 | 18 | 0.0% |
| 393.53A | “No Automatic Brake Adjuster for Hydraulic Brake Systems for vehicle manufactured on or after 10/20/1993” | 4 | 6 | 0.0% |
How it scores (violation points)
How it scores: in FMCSA's Safety Measurement System each violation counts its severity weight, plus 2 if it put the driver or vehicle out of service, times 3 in its first 6 months, 2 from 6 to 12 months, and 1 from 12 to 24 months. FMCSA has approved a simpler scale that is not live yet.
How to fix it
- Replace the failed automatic slack adjuster; do not keep adjusting it by hand.
- Check the other adjusters on the same axle and combination.
Stop it happening again
- Measure stroke at every service; a stroke that keeps growing is the early sign.
Challenging it in DataQs
Use DataQs (dataqs.fmcsa.dot.gov) only when the report is wrong: the wrong carrier or vehicle, a violation that did not happen, or a citation a court dismissed without a fine or found you not guilty of, which removes it from the Safety Measurement System; a conviction of a different charge lowers its weight to 1 (FMCSA adjudicated citations policy). Fixing the defect afterward is not a reason to remove it; keep the repair record instead.
FileFlo reads your public FMCSA record, lists every violation with the rule behind it, and keeps the driver and vehicle records that stop repeats.
Run it yourself: the Audit-Ready Setup, $499 through December 31, 2026, then $199 a month for up to 15 trucks. Or FileFlo runs it: $1,500 a month for up to 15 trucks, Setup included, and your first month back if you are not happy.
About these numbers
Counts are violations cited in roadside inspections used in FMCSA's Safety Measurement System from September 25, 2024 to September 24, 2026 (dataset 8mt8-2mdr on data.transportation.gov, October 2026 run). Carriers with 5 to 50 trucks means 66,936 active interstate for-hire carriers with 5 to 50 power units and more trucks than buses, based in the 50 states or DC, from FMCSA's census file. This is FileFlo's reading of public FMCSA data, not an FMCSA rating. Severity weights are the current SMS weights.