National Crane 1-21-2019 Control # 104-07 5-7
1400A SERVICE MANUAL HOIST
17. Fill both the gearbox and the brake section with the
proper amount and type of lubricants. See Section 8
Lubrication.
HOIST SERVICE
Brake
NOTE: See Figure 5-7 for item number (#) identification.
1. Evenly remove the four capscrews (11) holding the
brake cover (20) in place. Spring pressure will raise the
cover up as the capscrews are loosened. Remove the
cover from the brake housing.
2. Remove the springs (24) from the piston and check the
springs for free height. Each spring should measure at
least 1.200 inches with no force.
3. To remove the brake piston (10), install two pieces of all-
thread (3/8-16NC) in the bottom of two spring pockets.
4. Using jam nuts, screw the all-thread pieces in evenly
until the piston is clear of the housing. An alternate way
of removing the piston is to use shop air to slowly
pressurize the brake cavity until the piston is out of the
bore.
5. Grasp the brake driver/clutch assembly (Items 38, 13,
23, 14, 15 & 17) and remove it from the brake housing.
6. Remove the stator plates (19) and friction discs (18)
from the brake housing and check for excessive wear.
Be sure to check the top stator plate for scoring caused
by the removal tools and polish if necessary. Friction
discs should measure no less than 0.055 in. thickness
and stator plates should measure no less than 0.068 in.
thickness.
7. With a hook wire or pry bar, remove the seal (7-5).
8. Examine the bushing (39) in the brake housing for wear
and replace if necessary.
9. If brake housing (21) is removed from the hoist, examine
the journal on the brake housing where the seal (7-4)
runs for wear. If severely worn, replace the brake
housing.
10. Carefully disassemble the brake driver/clutch assembly
noting the direction of lockup for the clutch (34). The
clutch assembly must be re-assembled with the arrow
pointing in the proper direction for the hoist to function
properly. Inspect the O. D. on the input driver (38) and
I. D. of the brake driver (13) where the clutch (34) runs. If
there is any pitting or spalling on the driver then it and
the clutch must be replaced.
11. Re-assemble the driver/clutch assembly, making sure
that the clutch is installed properly.
12. Install a new seal (7-5) into the brake housing. If the
brake housing is removed from the hoist temporarily
install the input sun gear into the brake housing, and
slide the driver/clutch assembly onto the sun gear
spline.
Fo
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