SUBSECTION 7C
DRUM BRAKES
GENERAL
As the lining wears, increasing the length of the lockspring
and the piston extension of the brake cylinder, the brakes
This subsection contains the information necessary to re-
will need adjusting. See the Operator's Manual for the
move, repair, install and adjust the main brakes and plane-
method of adjusting the brakes for normal lining wear.
tary brakes.
The main brakes should be relined when brake lining thick-
Several terms are often misunderstood when used in ref-
ness reaches 3/16 inch as measured at the dead end of the
erence to brake bands on this machine. The following de-
band.
finitions, as used in this manual, are as follows:
REMOVAL. To remove the main brake bands, proceed as
1. Brake Set. This means the brake band is tightened
follows {see Figure 7C-2):
around a rotating member to stop or prevent the rotation of
that member.
1. Shut down the engine and operate a control lever until
all hydraulic pressure is exhausted from the system.
2. Live End. This is the end of a brake band to which force is
applied.
2. If any rope remains on the drum to be worked on, set the
drum pawl to prevent the rotation of the drum.
3. Dead End. This is the anchor end of a brake band.
Typically, most lining wear will occur at this end of the band.
3. Remove the sheet metal from around the brake band to
be worked on.
4. Release the tension on the hanger springs by loosening
MAIN BRAKE (9215J107)
the turnbuckles. Remove the hanger springs from the band.
DESCRIPTION. Both the left and right main brake bands are
5. Remove the brake band adjusting bolt and spring by re-
connected to two hydraulic cylinders with opposing springs
moving the nut and spacer.
(see Figure 7C-1). When there is no pressure in the lock cyl-
6. Remove the dead end link pin to free the dead end of the
inder, each brake is set by the lock spring which opposes the
band from the dead end links. Remove the live end pin to
lock cylinder. When the operator moves a brake lock switch
free the live end of the band from the actuating levers.
to the OFF position, hydraulic pressure is applied to the lock
cylinder, extending the piston and compressing the lock
7. Remove the brake band halves from the machine and re-
spring. This releases the brake so that it may be operated by
line them.
the foot brake.
NOTE
When the operator depresses the foot brake pedal, hydrau-
A lining kit is available. See the Replacement Parts
lic pressure is applied to the brake cylinder, extending the
Manual.
piston and setting the brake. When the operator releases
8. After replacing the lining on the brake bands, file the lin-
the brake pedal, hydraulic pressure is released from the
ings with a half round file, or sandpaper, to take out the high
brake cylinder, retracting the piston and releasing the
spots. This will assure total contact with the drum.
brake. A return spring is used to assist in releasing the
brake and retracting the piston.
9. Bevel the edges between each segment of the lining.
This will reduce drag on the drum. Be sure to remove all fil-
When the brake linings are new and the brakes are in
ing dust from the rivet holes prior to installation.
proper adjustment, two dimensions should be noted. With
the brake set and hydraulic pressure released from the cyl-
INSPECTION AND REPAIR. Before reinstalling the band
inders, the length of the lock spring should be 7-3/4 inches
halves on the drum, inspect the following items:
and the piston extension of the brake cylinder should be 1/8
inch.
1. Check all the springs for sufficient compression. Re-
place any weak springs.
When the brake linings start to wear, two things happen.
With the brake set and hydraulic pressure released from the
2. Inspect all pins, bushings and linkages for wear. Re-
cylinders the length of the lock spring and the piston exten-
place any worn parts. Also, check that links, levers, and pins
sion of the brake cylinder should increase.
are not bent.
