Hub And Drum Maintenance - Landoll 334C Operator's Manual

4-10 HUB AND DRUM MAINTENANCE

4-10.1 Clean and inspect the brake drums
whenever relining the brakes. To be suitable
for further service, the brake drum should
pass the following checks.
a. The brake surface should be free of scoring,
excessive heat checks and cracks.
b. The brake surface diameter should be within
the maximum diameter cast or stamped on
the drum.
c. The mounting holes and pilot must be round
and true.
d. The mounting surface must be clean and
flat.
WARNING
F A I LU R E TO R EP LA CE FAU LT Y
BRAKE DRUMS WILL RESULT IN AN
UNRELIABLE BRAKING SYSTEM, AND
MAY LEAD TO AN ACCIDENT.
4-10.2 It may be necessary to turn or resurface
the braking surface to remove small heat
checks or other surface defects resulting
from normal use.
a. The maximum diameter cast into the back
plate portion of the brake drum is the maxi-
mum diameter or discard diameter to which
the brake drum may be turned or worn and
still be usable. If any portion of the brake sur-
face exceeds the maximum diameter it must
be discarded. The maximum is .120 over the
nominal new diameter unless stated other-
wise on the casting. The maximum diameter
cast into the brake drum supersedes all pub-
lished information.
b. When resurfacing a drum, allow at least
0.040 inches under the maximum diameter
for additional wear.
WARNING
TURNING A BRAKE DRUM BEYOND
0.040 INCHES UNDER THE MAXIMUM
D I A M E TE R W I LL R E S U L T I N A
WEAKER BRAKE DRUM AND MAY RE-
SULT IN AN ACCIDENT.
4-10.3 Replacement of the brake drum is re-
quired if any of the following conditions exist:
a. The brake drum is cracked.
b. The brake surface is heat checked, grooved
or worn beyond the rebore limit or the maxi-
mum diameter.
c. The back plate is cracked.
d. The bolt holes are elongated.
e. The brake drum has been severely over-
heated.
f. The brake drum is out-of-round.
CAUTION
REPLACE BRAKE DRUMS IN PAIRS
TO ACHIEVE THE SAME BRAKING
POWER ON BOTH WHEELS AND
MAINTAIN AN EVEN BRAKING LOAD
ON THE AXLE. FAILURE TO DO THIS
MAY SIGNIFICANTLY REDUCE THE
P E R FO R MA N C E , S E R V I C E L I FE ,
AND/OR SAFETY OF YOUR VEHICLE.
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