National Crane
Published 5-27-2018 Control # 039-06
11-11
800D
HOIST
SERVICING THE BRAKE
1. Evenly remove the four capscrews (11, Figure 11-8)
holding the brake cover (20) in place. Spring pressure
will raise the cover as the capscrews are loosened.
Remove the cover from the brake housing.
2. Remove the springs (24) from the piston and check the
free height. Each spring should measure at least 1.200
in with no force on them.
3. Remove the brake piston (10) by installing two pieces of
3/8 in-16NC all-thread in the bottom of two spring
pockets. 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 a portable
power unit or shop air to slowly pressurize the brake
cavity until the piston is out of the bore.
4. Remove the brake driver/clutch assembly (13, 14, 15,
17, 34, and 38) from the brake housing (21).
5. Remove the stator plates (19) and friction discs (18)
from the brake housing and check them for excessive
wear, then replace if necessary. Additionally, 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 thick and stator plates should
measure no less than 0.064 inches thick.
6. If necessary, with a hook wire or pry bar, remove the seal
(7-5) from the brake housing.
7. Examine the bushing (39) in the brake housing for wear
and, if worn, replace it.
8. If the 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.
9. Carefully disassemble the brake driver/clutch and note
the side in which the markings on the clutch (34) are
facing. The clutch assembly must be re-assembled with
the markings facing the proper direction in order for the
hoist to function properly. Inspect the surface on the
input and brake drivers (13 & 38) where the clutch (34)
runs. If there is any pitting or spalling on the drivers then
both it and the clutch must be replaced.
10. Re-assemble the driver/clutch assembly, making sure
that the clutch is installed properly.
11. 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 (8) into the brake housing and
slide the driver/clutch assembly onto the sun gear
spline.
12. Install the stator plates (19) and friction discs (Item 18)
into the brake housing starting with a stator and
alternating friction discs and stator plates. There is one
more stator plate than friction disc so you will finish with
a stator plate.
13. Coat the new o-rings and backup rings (7-1, 7-6, 7-7, &
7-8) with light oil and install onto the piston (10). See
Figure 11-8 for proper o-ring/backup ring installation.
14. Carefully install the piston (10) into the brake housing
(21) and gently tap it down until it is seated.
15. Install the springs (24) into the spring pockets of the
piston. If working in a horizontal position, coat the
bottom of each spring with chassis lube to keep it in
position.
16. Coat the new o-ring (7-3) with light oil and install it into
the groove on the brake cover (20).
17. Install the cover (20) onto the brake housing (21) and
draw it down evenly, alternating between opposite
capscrews (11). Make sure that the cover is aligned
properly with the brake housing in order to correctly
orient the motor and vent/drain plugs.
18. Check the brake release with a portable hydraulic pump.
Full release should be obtained at 225 PSI ±10%.
Fo
r
Reference
Only
Содержание National Crane 800D
Страница 1: ...Operator and Service Manual National Crane 800D F o r R e f e r e n c e O n l y ...
Страница 4: ...F o r R e f e r e n c e O n l y ...
Страница 98: ...MAINTENANCE 800D 3 10 Published 5 27 2018 Control 039 06 THIS PAGE BLANK F o r R e f e r e n c e O n l y ...
Страница 194: ...SPECIFICATIONS 800D 8 4 Published 5 27 2018 Control 039 06 THIS PAGE BLANK F o r R e f e r e n c e O n l y ...
Страница 216: ...INSTALLATION 800D 9 22 Published 5 27 2018 Control 039 06 THIS PAGE BLANK F o r R e f e r e n c e O n l y ...
Страница 232: ...CRANE INSTALLATION 800D 10 16 Published 5 27 2018 Control 039 06 THIS PAGE BLANK F o r R e f e r e n c e O n l y ...
Страница 252: ...SCHEMATICS 800D 2 Published 5 27 2018 Control 039 06 F o r R e f e r e n c e O n l y ...
Страница 255: ...F o r R e f e r e n c e O n l y ...
Страница 256: ...F o r R e f e r e n c e O n l y ...