# NHTSA Engineering Analysis EA07016
> **OVERHEATING DISC BRAKE CALIPER** · Opened 2007-11-16 · Closed 2009-08-19
## Investigation
- **Action number:** EA07016
- **Type:** Engineering Analysis
- **Open date:** 2007-11-16
- **Close date:** 2009-08-19
- **Manufacturer:** WORKHORSE CUSTOM CHASSIS
- **Affected makes:** WORKHORSE
- **Affected components:** SERVICE BRAKES, HYDRAULIC
- **Affected model years:** 2000, 2001, 2002, 2003, 2004, 2005
- **Affected (make, year) variants:** 98
## Summary

THE EA WAS OPENED TO GAIN A TECHNICAL UNDERSTANDING OF THE CAUSES FOR ONE OR MORE DISC BRAKE CALIPERS ON A SUBJECT VEHICLE TO SUFFER SEVERE OVERHEATING. THE OVERHEATING CAUSED BRAKE DRAG, MELTING ABS SENSORS, SMOKING, BRAKE LINING FIRES, AND IN SOME CASES BOILING BRAKE FLUID RESULTING IN DIMINISHED STOPPING CAPABILITY.BASED ON TESTING, WARRANTY AND COMPLAINT DATA ANALYSIS, FIELD TRIPS AND INTERVIEWS WITH OWNERS, MECHANICS AND SERVICE MANAGERS, ODI BELIEVES THE LIKELY CAUSE OF THE ALLEGED DEFECT IS WATER SWELL OF THE PHENOLIC CALIPER PISTON AND SUBSEQUENT FAILURE OF THE PISTON TO FULLY RETURN AFTER THE PEDAL IS RELEASED.A TECHNICAL REPORT IS ATTACHED WITH FULL DETAILS.

## Source
- [NHTSA ODI investigation page](https://www-odi.nhtsa.dot.gov/owners/SearchResults?searchType=ID&targetCategory=I&searchCriteria.nhtsa_ids=EA07016)
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