Investigation EA84026: Vehicles

Status

CLOSED

Opened

Aug 15, 1984

Closed

Apr 8, 1988

Model years

—

Subject

Rear brake lockup

Summary

Summary: the rear cylinder diameter was reduced for 1984 models to improvebraking balance for empty vehicles.gm claims rear brakes can be lockedon most empty pickups on low traction surfaces.analysis:pickup trucks traditionally have been designed with brakingsystems which caused the rear brakes to lock first when the cargo bed isempty, so that maximum effective braking is available when a load ispresent. Most modern light trucks and vans utilize weight sensitive prop-ortioning valves to provide good braking at all loads.status:c-memo may need revision.in final by 12/31/87.===

An NHTSA investigation looks into whether a safety defect exists. Opening one is not a finding. Outcomes can include a recall, closure without action, or further inquiry.