Chambers ( S e m i t r a i l e r s M 2 7 0 a n d M 2 6 9 ) .
Brake air chambers (fig. 18) are mounted on brackets adjacent
and at the rear of the rear-rear axle.
They convert air pres-
sure into mechanical motion to operate the slack adjusters.
n. slack Adjusters (Semitailers M270 and M269). T h e s l a c k
adjusters (fig.18) are levers mounted on the brake camshafts.
They are operated by the push rods of the brake air chambers
to rotate the camshafts and cause the cams to press the brake
shoes against the brake drums.
Provision is made to adjust
the angle of the slack adjuster on the camshaft to afford the
most efficient brake operation.
This is obtained when the travel
of the arm of the slack adjuster is held to a minimum and full
leverage is used. Such adjustment is termed the minor adjust-
ment of the brakes (par. 56c).
11. Hubs and Brake Drums
The brake drums and wheels are mounted on
the hubs. Each hub is mounted on the spindle of its axle on
The wheels are mounted on the
two taped roller bearings.
hub with 10 wheel studs, cap nuts, a n d w h e e l n u t s . C a p n u t s
and wheel nuts on the right side of t h e v e h i c l e h a v e r i g h t - h a n d
threads and are marked R. Those on the left side have left-
Wheel nuts and cap nuts