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Problem
Cause
Solution
D. Blue or discolored brake surface
Bluing is typically caused
by excessive heat from
dragging brakes or brake
imbalance.
Brake system should be checked
for balance and properly adjusted
slacks. Replace brake drum if heavy
heat check develops.
E. Scale on outside
Excessive heat
Check brake balance, weak or
broken return springs, brake
adjustment and lining. Type within
vehicle combination.
F. Heat Spotted or hard spots in brake surface
Highly localized heating
and cooling cycles typically
caused by brake drag or
torque imbalance. These
dark colored spots are the
result of martensite forming
in the cast iron braking
surface.
Replace brake drum
G. Out-of-Round
G1.
NO PHOTO AVAILABLE
G1.
Balance
G1.
Balanced drum not
specified or drum was
improperly handled or
installed.
G1.
Specify balanced brake drums when
ordering. Review proper handling
and installation procedures.
G2.
NO PHOTO AVAILABLE
G2.
Variation in
diameter
G2.
Heat distortion.
G2.
Rebore brake drum within normal
limits or replace. See (A2) Turning
the Brake Surface.
G3.
NO PHOTO AVAILABLE
G3.
Concentricity
G3.
Improper fit to pilot or
improper seating on wheel
or hub.
G3.
Clean all mounting surfaces. Check
for correct fit and clearance to
wheel.
BRAKE DRUM AND ROTOR SERVICE INFORMATION
TROUBLE-SHOOTING: BRAKE DRUM WEAR