What FMCSR 396.5-HL covers
396.5-HL identifies a leaking wheel hub — oil or grease weeping past the hub seal on a steer, drive, or trailer axle. It is recorded in the Vehicle Maintenance category. The code does not carry an FMCSA-normalized severity weight in the definition record, but the enforcement data speaks for itself.
A leaking hub is not a cosmetic defect. It means the seal is compromised; it means the bearing is running drier than design; it means wheel separation is on the failure path. Inspectors treat it as immediate-attention, and the out-of-service numbers reflect that.
What our enforcement data actually shows
Across 5,931 all-time citations our database records 4,537 OOS placements — a 76.5% out-of-service rate. This is more than double the all-FMCSR average OOS rate of 31.4% across our 3,036 code dictionary.
396.5-HL is ranked #307 by volume — not a high-frequency code — but the per-citation severity is extreme. When an inspector writes it, the truck rarely rolls away on the same wheel.
The code is also active. The last 12 months hold 3,944 citations, the last 90 days hold 803, and the monthly trend has grown from 131 in April 2025 to a peak of 456 in August 2025 before settling around 300–376 through early 2026. The rolling volume is meaningful.
The state signature is the most striking in our data
Half the top-ten states show a 100% out-of-service rate on 396.5-HL:
- California — 601 citations, 220 OOS, 36.6% OOS rate
- Florida — 84 citations, 84 OOS, 100% OOS
- Pennsylvania — 81 citations, 49 OOS, 60.5% OOS rate
- Arizona — 76 citations, 76 OOS, 100% OOS
- Utah — 67 citations, 67 OOS, 100% OOS
- Missouri — 67 citations, 67 OOS, 100% OOS
- Tennessee — 52 citations, 52 OOS, 100% OOS
- Ohio — 46 citations, 46 OOS, 100% OOS
- Georgia — 43 citations, 43 OOS, 100% OOS
California is the high-volume state and the only major one that lets some leaking-hub tractors roll. In Florida, Arizona, Utah, Missouri, Tennessee, Ohio, and Georgia, inspectors writing 396.5-HL are deadlining the vehicle every time.
Who gets cited
The top carriers by 396.5-HL count are large long-haul fleets with heavy tractor utilization:
- WESTERN EXPRESS INC — 26 citations
- SWIFT TRANSPORTATION CO OF ARIZONA LLC — 23 citations
- SCHNEIDER NATIONAL CARRIERS INC — 20 citations
- FEDERAL EXPRESS CORPORATION — 18 citations
- J B HUNT TRANSPORT INC — 18 citations
- UNITED PARCEL SERVICE INC — 16 citations
- US XPRESS INC — 16 citations
Peer-comparable fleets: this is an equipment-aging problem, not a company-culture problem. High-mile tractors accumulate hub-seal wear at a predictable pace. The dominant makes in our 396.5-HL records are Freightliner (949 citations under “FREIGHTLIN” plus 899 under “FRHT”), Kenworth (383), and Peterbilt (310) — the long-haul fleet composition of the United States.
How it compares to similar codes
Vehicle Maintenance category peers show how unusual 396.5-HL is:
- 396.3(a)(1) (general maintenance) — 236,919 events, 45.3% OOS
- 393.9(a) (inoperable lamps) — 660,737 events, 15.4% OOS
- 393.9 (lamp, bare) — 180,097 events, 6.9% OOS
- 393.11 (lighting) — 179,734 events, 1.8% OOS
A 76.5% OOS rate is not approached by any of the high-frequency peers in the same category. The code acts more like a brake-out-of-service citation than a maintenance citation.
How to avoid a leaking-hub citation
The co-occurrence pattern is where the prevention program lives. In our last-90-day data 396.5-HL travels with:
- 396.3A1-BOS — “BRAKES OUT OF SERVICE: 20%+ defective brakes” — 86 co-occurrences. The same tractor that is leaking at the hub usually has a brake issue the inspector will also find.
- 396.5B-L — fuel system leak (letter form) — 86 co-occurrences. Seal failures cluster: when one seal goes, the next is already compromised.
- 393.75A3-TAOL — tire inflation ≤50% on non-ATIS axle — 86 co-occurrences. The same maintenance gap that produces hub leaks also produces tire neglect.
- 393.47E — slack adjuster defective — 84 co-occurrences.
- 393.53B-B — worn steering component — 62 co-occurrences.
- 393.45D-B — brake tubing/hoses inadequate — 53 co-occurrences.
The prevention picture is clear: inspect hub seals on every PM cycle, with a wiping-cloth check on the brake drum face; replace seals on a time-based schedule for high-mile tractors; and run a combined brake/hub/tire audit rather than single-axis inspections. The tractors that show up in our 76.5%-OOS column are the tractors where one deferred maintenance item has pulled three or four others along with it.