SUBSECTION 7C
DRUM BRAKES
1. Check the springs for sufficient tension. Replace any
PLANETARY BRAKES (9215J107-14)
weak springs.
DESCRIPTION. The left and right drum planetary brakes are
2. Inspect all pins, bushings and linkages for wear. Re-
provided with power lowering on these drums and are
place any worn parts. Also checkthat links, guides, and pins
mounted over the planetary spiders. These brakes are
are not bent.
hydraulically set, spring released type brakes. When there
is no pressure in the planetary brake cylinder, its piston is
3. If the operating cylinders leak or have been performing
retracted and the planetary brake is held in the released
erratically, remove and overhaul if necessary. See Subsec-
position by springs.
tion 5D.
When the operator engages a planetary brake by means of
4. Check the brake bands for distortion.
the control lever, hydraulic fluid is directed to the planetary
5. Inspect the brake drum surfaces for cracks, scoring or
brake cylinder. With hydraulic pressure applied to the cyl-
other damage.
inder, its piston extends and applies force to the linkage
which contracts the brake bands and sets the brake (see
INSTALLATION. After relining the brake bands, install the
band halves as follows (see Figure 7C-5):
When the linings are new and the brakes are in proper ad-
1. Install the band halves on the drum. Install the live end
pin through the actuating levers and the live end of the
justment, the length of the cylinder piston extension with
band. Install the dead end pin through the dead end links
the brake set (hydraulic pressure applied) should be 5/8
inch. When the brake lining starts to wear, this dimension
and the dead end of the band. Install all cotter pins.
will increase (with the brake set). See the Operator's Man-
2. Install the spring, adjusting bolt and spacer on the band
ual for the method of adjusting the brakes for normal lining
halves. Hold these items in place with the adjusting nut.
wear.
3. Install the hanger springs on the brake band. Initially ad-
The planetary brakes should be relined when brake lining
just the hanger springs with the turnbuckles so that the
thickness reaches 3/16 inch as measued at the dead end of
brake band clears the drum.
the band.
4. Bleed the hydraulic cylinders to remove any air trapped
in the hydraulic lines. See the Bleeding Procedure in Sub-
REMOVAL. To remove the planetary brake bands, proceed
section 5A.
as follows (see Figure 7C-5):
ADJUSTMENT. To adjust the planetary brakes when the
1. Shut down the engine and operate a control lever until
bands have been removed, proceed as follows (see Figure
all hydraulic pressure is exhausted from the system.
7C-4):
2. If any rope remains on the drum to be worked on, set the
1. With the planetary brake released, check the piston ex-
drum pawl to prevent rotation of the drum.
tension of the cylinder. The piston should extend a mini-
3. Remove the sheet metal from around the brake band to
mum of 1/8 inch; if not, adjust by means of adjusting nut
be worked on.
"C".
4. Release the tension on the hanger springs by loosening
2. With the brake set (hydraulic pressure to the cylinder)
the turnbuckles. Remove the hanger springs from the band.
the length of the piston extension should be 5/8 inch. Ad-
just the brake band adjusting bolt until this dimension is
5. Remove the brake band adjusting bolt and spring by re-
reached.
moving the nut and spacer.
NOTE
6. Remove the dead end link pin to free the dead end of the
band from the dead end links. Remove the live end pin to
Loosening the brake band adjusting bolt will in-
free the live end of the band from the actuating levers.
crease the piston extension. Tightening the adjust-
ing bolt will decrease the piston extension.
7. Remove the brake band halves from the machine and re-
line them.
3. After the machine has been operated long enough to
NOTE
warm the drums and the brakes have been properly ad-
justed, check the adjustment of the hanger springs. The
A lining kit is available. See the Replacement Parts
hanger springs should be adjusted so that the brake band
Manual.
clears the drum uniformly around its circumference, with
8. After replacing the lining on the brake bands, file the lin-
the brake in the released position (hydraulic pressure re-
ings with a half round file, or sandpaper, to take out the high
leased).
spots. This will assure total contact with the drum.
4. Recheck dimensions given in steps 1 and 2 with the
9. Bevel the edges between each segment of the lining.
brakes warmed and adjust as necessary. Be sure that pin
This will reduce drag on the drum. Be sure to remove all
"D" does not come in contact with slot "F"of link "K". If this
filing dust from the rivet holes prior to installation.
occurs, step 1 and 2 must be repeated to eliminate the pin to
INSPECTION AND REPAIR. Before reinstalling the band
slot contact.
halves on the drum, inspect the following items (see Figure
5. Replace any sheet metal removed.
7C-5):
7C-5
