Investigation PE86073: Vehicles

Status

CLOSED

Opened

Aug 13, 1986

Closed

Oct 16, 1986

Model years

—

Subject

Ineffective air brakes

Component: Service brakes, hydraulic

Summary

Summary of information from manufacturer:none at this time.analysis:a pneumatic balance test performed on four of the subject busesby aftermarket brake system distributor indicated that during a 15 psibrake application, there would be 15 psi at the front axle and 0 psi atthe rear.one of the keys to brake balance is brake actuation and release.the rear should apply before the front and release slightly after.sincemost braking occurs below 20 psi, it would seem that having the same orclose pressure in all chambers is important for proper balance.proposed action:open a pe.send an ir.

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.