AIR BRAKES - GENERAL INFORMATION
Condition 3
Due to their design, some tandem axles were not
changed
with
the
introduction
of
FMVSS
121.
Application of the power divider lock remains the same
as CONDITION 1. These tandem axles have spring
brake chambers at each rear axle brake group. There
are also some axle code applications which have been
released since FMVSS 121 regulation went into effect
that apply to this condition.
Identification by the number of spring brake chambers
cannot be used since some vehicles under CONDITION
2 may have spring brake chambers at all rear axle brake
groups. Rear axles with a GAWR of 44,000 lb. (20,000
kg) and above will have a spring brake chamber at each
brake.
Figure 19 - 6x4 Tractor With Initial Split Air System With Modular Control Valve
For Spring Brake and Tractor Protection Control
CTS-4154Y - Page 17
