Engineering Analysis · RETURN SPRING · Opened 1989-08-29 · Closed 1990-11-16
Investigation
Action number
EA89035
Type
Engineering Analysis
Open date
1989-08-29
Close date
1990-11-16
Manufacturer
Williams Controls, Inc.
Affected makes
WILLIAMS
Affected components
VEHICLE SPEED CONTROL:LINKAGES
Affected model years
1985, 1986, 1987, 1988, 9999
Affected (make, year) variants
10
Summary
SUMMARY:SUBJECT ELECTRONIC PEDALS ARE EQUIPPED WITH A DOUBLE RETURNSPRING.TWO UNITS REPORTEDLY HAVE COMPLETELY FAILED, WITH SEVERAL OTHERSEXPERIENCING A SINGLE SPRING FAILURE.WILLIAMS ATTEMPTED TO ADDRESS THEISSUE WITH A SERVICE BULLETIN MANDATING AN ANNUAL INSPECTION OF THE SUBJECTSPRINGS, AND BIANNUAL REPLACEMENT.THIS PROCEDURE IS DEEMED UNREALISTICFOR OVER THE ROAD TRUCK OPERATORS.FAILURE OF THE SPRINGS RESULTS IN WIDEOPEN THROTTLE.WILLIAMS CURRENTLY IS CONDUCTING A FLEET SURVEY ANDADDITIONAL DURABILITY TESTING TO DETERMINE THE MAGNITUDE OF THE PROBLEM.AT LEAST TWO TRUCKS MANUFACTURERS HAVE ISSUED STRONGLY WORDED SERVICEBULLETINS CONCERNING THIS MATTER.THIS PROBLEM APPEARS TO HAVE SAFETYIMPLICATIONS.ADDITIONAL INFORMATION IS NEEDED.===