GMC W SERIES 1977: SERVICE BRAKES, AIR:ANTILOCK:CONTROL UNIT/MODULE

Make : GMC Model : W SERIES Year : 1977
Build Dates : 1975-02-01 - 1979-03-01
NHTSA CAMPAIGN ID Number : 79V077000
Date Owner's Notified: 1979-11-09 Date Received by ODI: 1979-03-29 Date Added to Database: 1979-10-12
Manufacturers Involved: Ford Motor Company
Manufacturer's Responsible for the Recall:
Manufacturer Campaign Number:
Component: SERVICE BRAKES, AIR:ANTILOCK:CONTROL UNIT/MODULE
Potential Number Of Units Affected : 65000
Summary:
      CERTAIN AIR BRAKE ANTI-LOCK MODULATORS COULD MALFUNCTION DURING OPERATION OF THE ANTI-LOCK SYSTEM. A NYLON PISTON WITHIN THE MODULATOR AIR VALVE SYSTEM CAN SWELL FROM EXPOSURE TO SYSTEM CONTAMINANTS. CONTINUED EXPOSURE MAY CAUSE THE PISTON TO SWELL TO THE EXTENT THAT INTERFERENCE WITH THE CYLINDER WALL WILL RESULT, CAUSING MOMENTARY STICKING OR A PERMANENT JAM. THIS CAN RESULT IN TEMPORARY OR PERMANENT LOSS OF BRAKING FOR THE AFFECTED AXLE.
Consequence:
     
Remedy:
      THE PISTONS IN THE VALVE PORTION OF THE MODULATORS WILL BE REPLACED WITH PISTONS THAT DO NOT SWELL WHEN EXPOSED TO AIR BRAKE SYSTEM CONTAMINANTS.
Report Initiator: MFR V Report
Regulation Part Number: Federal Motor Vehicle Safety Standard Number:
Notes:
      VEHICLE DESCRIPTION: HEAVY TRUCKS EQUIPPED WITH ANTI-LOCK AIR BRAKECONTROLLERS.SYSTEM: SERVICE BRAKES; CONTROL ASSEMBLY.