What 393.45B3 means in plain language
When a CVSA inspector issues a 393.45B3 citation, they've found that your commercial motor vehicle's brake tubing or hoses are in compromised condition. This covers tubing or hoses that are worn, chafed, crimped, or otherwise damaged—anything that degrades their structural integrity or flow capacity.
Brake lines are critical. They carry pressurized fluid that stops your rig. Even minor damage can lead to slow leaks, loss of braking pressure, or catastrophic failure under hard braking. An inspector doesn't need to see active brake failure; spotting visible wear, cracks, abrasion against frame components, or improper crimps is enough to cite this violation.
What our enforcement data actually shows
Across our 13 million+ inspection records, 393.45B3 ranks #2083 out of 3,036 FMCSR codes by citation volume. We've recorded 14 all-time citations for this code, with 11 citations in the last 12 months and 6 in the last 90 days.
Out of those 14 all-time citations, 4 vehicles were placed out of service, yielding a 28.6% out-of-service rate. This sits slightly below the all-FMCSR average out-of-service rate of 31.4%, suggesting that while brake tubing damage is serious enough to sideline roughly 1 in 3.5 cited vehicles, inspectors often cite it as a defect requiring repair but not immediate removal from service.
The citation trend shows modest but steady enforcement: 3 citations in May 2025, dropping to 1 in June, then rising to 3 again in February 2026. This pattern indicates that inspectors catch brake tubing issues year-round, with no sharp seasonal spike.
Who gets cited most
Our data shows citations concentrating in two states over the last 180 days. Texas led with 5 citations and 1 out-of-service placement (20.0% OOS rate), while Iowa recorded 1 citation with no out-of-service action (0.0% rate).
Among carriers in our all-time database, no single fleet dominates this violation; citations are spread across specialized transport operators. Our records show carriers such as Transportes de Carga Saul Salinas SA de CV (USDOT 557676), Transportes Especializados RG SA de CV (USDOT 998029), and others, each with 1 citation. This distribution suggests brake tubing damage is an individual-vehicle issue rather than a fleet-wide compliance pattern.
How severe is this compared to similar codes
Brake-system violations fall within the Vehicle Maintenance category. Looking at peer codes:
393.9(a) — Inoperable required lamps has been cited 660,737 times with a 15.4% out-of-service rate, making it vastly more common but less likely to sideline a vehicle.
396.3(a)(1) — Inspection/repair/maintenance (general) shows 236,919 citations and a 45.3% out-of-service rate, meaning it lands vehicles out of service nearly twice as often as 393.45B3.
393.47E — Slack adjuster defective has 180,363 citations but a 0.0% out-of-service rate in our database, indicating inspectors often cite it as a reportable defect without immediately removing the vehicle.
Brake tubing damage falls in the middle: rarer than lamp or general maintenance issues, but serious enough to trigger out-of-service action in over 1 in 4 cases.
How to avoid it
Our inspection data reveals patterns of what commonly co-occurs with 393.45B3 citations, pointing to concrete prevention steps:
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Perform detailed pre-trip brake-system inspections. In 4 recent inspections where 393.45B3 was cited, inspectors also found issues with code 393.45B2UV (brake tubing/hoses inadequate, ultraviolet damage variant), suggesting that tubing damage is often widespread when one section fails. Walk the full length of all brake lines under the vehicle and along the frame, checking for abrasion, discoloration, or visible cracks.
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Check for frame contact and chafing. Brake lines route through tight spaces. Tubing that has rubbed against sharp frame edges, suspension components, or other hardpoints will show wear spots or bare metal. Wrap or relocate any line showing visible abrasion.
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Inspect crimps and connections. Our data shows Kenworth vehicles (4 citations) and Freightliner units (3 citations) appearing in this violation most frequently, likely reflecting exposure across a large owner-operator and small-fleet base rather than inherent design flaw. Still, check all flared or crimped fittings for cracks radiating from the crimp zone, a sign of manufacturing defect or improper installation.
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Replace tubing on a preventive schedule. Brake lines degrade over time from heat, UV exposure, and vibration. If your rig is over 10 years old or has high-mileage, budget for brake line replacement as routine maintenance rather than waiting for an inspector to find damage.
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Pair brake-system checks with slack-adjuster inspection. Code 393.47E (slack adjuster defective) appears in 2 of the recent co-occurring violations with 393.45B3, suggesting that brakes fail together. When you inspect tubing, also manually check that slack adjusters move freely and that brake stroke is within spec.
A citation for 393.45B3 does not automatically result in out-of-service status—your vehicle has a 71.4% chance of passing inspection and continuing operation. However, the violation will appear on your record and in CSA metrics. The fastest path to resolution is immediate repair of the damaged section, documentation of the repair, and a follow-up inspection if required by your jurisdiction.