NHTSA complaint #638539 (ODI reference 10202938) concerns a 2004 WORKHORSE W20 and was filed on September 13, 2007. The owner reports the failure occurred on August 20, 2007. The vehicle had 20,100 miles on the odometer at the time of the incident. The report was geocoded to Tennessee based on the filer's self-reported location. The affected component is categorized as service brakes, hydraulic:foundation components:drum:wheel cylinders, one of NHTSA's standardized taxonomy codes used to group defect patterns across make, model, and year.

The filer flagged the following severity indicators: crash: no, fire: no, injuries: 0, fatalities: 0. No crash, fire, or fatality was associated with this report, which places it in the early-warning stream rather than the priority-review stream. Because a VIN was supplied, this complaint is tied to a specific vehicle and not just a model-year cohort.

Individual complaints are consumer-submitted and unverified by NHTSA engineers — the agency's role at this stage is to collect, index, and make them searchable. What matters for federal action is the pattern: when many owners of the same WORKHORSE W20 cohort independently describe similar service brakes, hydraulic:foundation components:drum:wheel cylinders failures, defect investigators have grounds to open a PE and request manufacturer data. Related filings for the same vehicle and component appear below, and the detail page for the full 2004 WORKHORSE W20 shows the complete component-level complaint distribution alongside any active investigations or recalls.