What 393.45B3-B means in plain language
Brake tubing and hoses are the arteries of your brake system. They carry pressurized brake fluid from the master cylinder to the wheel brakes on all four wheels. When these tubes or hoses are worn, chafed, crimped, or otherwise damaged, they can leak fluid, lose pressure, or fail entirely — and your brakes won't work.
This citation means an inspector found visible damage: fraying, cuts, dents, kinks, abrasion marks where the line rubs against frame or other components, or signs of leakage. It doesn't mean your brakes failed on the road. It means the tubing or hose itself is in a condition that the Federal Motor Carrier Safety Regulations don't permit.
The good news: this violation does not result in an out-of-service order at roadside. You can legally continue driving to a repair facility, though you should treat it as urgent.
What our enforcement data actually shows
Across our 13 million+ inspection records, 393.45B3-B ranks #1735 out of 3,036 FMCSR codes by citation volume. It is uncommon — only 35 all-time citations in our database, with 22 in the last 12 months and 2 in the last 90 days.
The OOS rate for this code is 0.0%: not a single vehicle has been placed out of service for a 393.45B3-B violation. This stands in stark contrast to the all-FMCSR average OOS rate of 31.4%, meaning this violation is enforcement-light and almost never removes a truck from service at the roadside.
Over the last 12 months, citations have been steady but sparse. In April 2025 there were 2, May had 3, June and August each had 4, and the remaining months ranged from 2 to 3. The pattern suggests this code is cited opportunistically during routine inspections rather than as a widespread compliance problem.
Who gets cited most
Our data from the last 180 days shows this violation is geographically scattered. California, Colorado, and New Jersey each recorded 1 citation. None resulted in an out-of-service order. The OOS rate across all three states is 0.0%.
Across all time, our records show fleets such as LINEWORKS LLC (USDOT 3257521) with 2 citations for this code. Most other carriers have encountered it only once. This is not a pattern of systematic non-compliance at any single fleet; rather, it appears in isolated inspections across many different motor carriers.
How severe is this compared to similar codes
Brake tubing and hoses fall under the vehicle maintenance category. Let's compare 393.45B3-B to closely related brake codes:
393.47E — Slack adjuster defective has been cited 180,363 times with a 0.0% OOS rate. That code also doesn't trigger out-of-service orders, but it is cited far more frequently—roughly 5,000 times more often than 393.45B3-B.
396.3(a)(1) — Inspection/repair/maintenance (general) shows 236,919 citations and a 45.3% OOS rate. This broader maintenance violation sends vehicles out of service at much higher frequency, indicating more serious defects.
393.9(a) — Inoperable required lamps has 660,737 citations with a 15.4% OOS rate. While also maintenance-related, lighting violations are cited roughly 19,000 times more often than brake tubing damage.
Your citation is rare and never results in roadside removal. It sits at the low end of severity for vehicle defects.
How to avoid it
Brake tubing and hoses degrade over time through exposure to heat, road salt, vibration, and abrasion. Here's what to do:
-
Before every trip, walk around your brake lines. On a pre-trip inspection, crouch down and visually inspect all visible brake tubing and hoses running along the frame, under the chassis, and to each wheel. Look for cracks, kinks, leaks (wet spots or stains), or areas where the line touches sharp edges or rubs against metal.
-
Check for chafing at common pressure points. Brake lines often rub where they pass through the frame or near suspension components. If you see shiny spots, missing paint, or exposed copper, that's a red flag. Secure loose lines with clips or wrap with protective material.
-
Pay attention if you share inspections with suspension or tire issues. Our data shows that 393.45B3-B sometimes appears in the same inspection as suspension defects, loose wheel fasteners, or tire inflation problems. If you're cited for one of these, do a full brake-system visual before your next run.
-
Know your vehicle. Freightliner and Kenworth models appear most frequently in our 393.45B3-B citations. If you drive one, be especially diligent about brake line inspection during pre-trip.
-
Address small damage immediately. A small cut or abrasion can expand into a catastrophic leak. If you notice any damage, get it inspected by a qualified technician before the next road cycle. A temporary repair is not compliant; you need proper replacement or re-routing of the line.
-
Keep records of brake system maintenance. Document when you inspect, clean, or replace brake tubing. This protects you in case of a future citation and shows you're proactive.
Brake tubing damage is preventable through routine visual inspection and prompt repair. Because the violation doesn't place you out of service, you have time to get it fixed—but don't delay. Brake failure is a safety emergency for you and everyone around you.