Investigations
PARK BRAKE SWITCH MALF
NHTSA Preliminary Evaluation PE87009 - closed, opened 1986-12-16.
NHTSA investigation PE87009 is a Preliminary Evaluation opened on 1986-12-16 and currently closed. The subject is tracked inside the Office of Defects Investigation queue. Latest activity on this investigation was logged on 1987-06-11 - NHTSA updates that field whenever an Information Request goes out, a supplement is filed, or a status change is recorded in the public docket.
A Preliminary Evaluation like PE87009 is the entry point of the federal defect-investigation process. NHTSA engineers scan complaint databases, field reports, and manufacturer data to decide whether an Engineering Analysis is warranted, whether a voluntary recall is already sufficient, or whether the pattern does not rise to a defect finding.
Investigators summarized the matter as follows: "SUMMARY OF INFORMATION FROM MANUFACTURER: SUBJECT VALVE WAS PRODUCED WITH-OUT AN INTERNAL SPRING TO KEEP THE PLUNGER IN THE APPLY POSITION. ASERVICE BULLETIN WAS PUBLISHED IN FEBRUARY, 1984 CONCERNING THE TIMELYREPLACEME..." Investigations are the early-warning layer of the federal auto-safety system, sitting upstream of formal recalls and defect orders. Whether this one closes without action or escalates into an Engineering Analysis, the full history stays in the ODI archive so researchers, litigators, and buyers can pull the paper trail at any time.
Investigation Summary
SUMMARY OF INFORMATION FROM MANUFACTURER: SUBJECT VALVE WAS PRODUCED WITH-OUT AN INTERNAL SPRING TO KEEP THE PLUNGER IN THE APPLY POSITION. ASERVICE BULLETIN WAS PUBLISHED IN FEBRUARY, 1984 CONCERNING THE TIMELYREPLACEMENT OF INTERNAL "O" RINGS IN THE VALVE WHICH IN TURN WILL PRODUCEADEQUATE FRICTION TO KEEP THE PLUNGER FROM DROPPING TO THE RELEASEPOSITION. IN MID-1986 A NEW PRESSURE SENSITIVE CONTROL VALVE,INCORPORATING A SPRING TO HOLD THE VALVE IN THE APPLY POSITION WASRELEASED. THIS VALVE WILL AUTOMATICALLY APPLY THE PARKING BRAKE IFPRESSURE IN THE SUPPLY TANK DIPS BELOW THE SET-POINT OF THE VALVE.ANALYSIS: IF THE SUBJECT MAINTENANCE WAS NOT PERFORMED, THE AIR SYSTEMWOULD HAVE TO LEAK DOWN AFTER THE PARKING BRAKE HAD BEEN APPLIED. IF THISOCCURRED AND THE O-RING IN THE VALVE WAS WORN ENOUGH, THE SPOOL MIGHT CREEPFROM THE APPLY TO THE RELEASE POSITION. THE PARKING BRAKE WOULD STILL BEAPPLIED. IF THE ENGINE WAS STARTED UNDER THESE CONDITIONS, THE INDICATORLIGHT ON THE DASH WOULD INDICATE THAT THE PARKING BRAKE WAS STILL APPLIED.IF THE DRIVER THEN DECIDED TO LEAVE THE BUS RUNNING UNATTENDED, THE AIRPRESSURE WOULD GRADUALLY BUILD UP RELEASING THE BRAKE; THE INDICATOR LIGHTSHOULD THEN GO OUT AND WITH THE DRIVER NOT IN THE DRIVER'S SEAT, THIS MIGHTGO UNNOTICED AND THE BUS MAY MOVE IF IT WAS PARKED ON AN INCLINE.PROPOSED ACTION: CLOSE THIS PE. NO SAFETY DEFECT TREND WAS IDENTIFIED.===
About This Investigation Type
A Preliminary Evaluation (PE) is the first phase of NHTSA's investigation process. It is opened when the agency identifies a potential safety defect pattern, usually triggered by consumer complaints, manufacturer reports, or field monitoring. During a PE, NHTSA gathers information to determine whether a formal engineering analysis is warranted.
Data from NHTSA Office of Defects Investigation. Cross-references: NHTSA recall campaign API and NHTSA FARS where fatality records overlap. PlainCars does not rate or recommend vehicles. about how PlainCars sources NHTSA data.
Read our methodology - how this data is sourced, computed, and verified.