Joyce DCD242 - Manual (Page 6)

6
Disassembly Procedure for KFTN (rotating screw) Models: see Figure 3-1
1. Remove the boot clamps (item #33) and collapse boots (item # 34) if the jack is
equipped with boots. Remove the traveling nut (item # 35) from the screw.
2. Loosen the (4) set screws (item # 5) in the sleeve cap and remove the sleeve cap by
rotating counter-clockwise (CCW.)
3. The screw assembly can now be removed from the jack sleeve. The screw assembly
consists of the lifting screw (item # 7), the upper thrust bearing (item #2), the key (item
# 36) and the wormgear (item # 3). First, the upper thrust bearing can be removed from
the assembly exposing the worm gear nut. Next, the worm gear nut can be separated
from the screw for replacement if necessary. (On inverted KFTN jacks it may be
necessary to remove the screw first.)
4. Remove screws (item # 16) from the bearing cap (item # 13). Remove the worm shaft
bearing cap and seals (item # 15) carefully to avoid damaging seals. Make sure keys
have been removed first.
5. Carefully remove the shims (item #12) from the jack sleeve or bearing cap. NOTE:
there will not necessarily be an equal quantity of shims per side. Keep track of the
number and order of shims on each side of the jack.
6. Remove the worm bearings (item # 11). The cup may be press-fit and require the use
of a dead-blow, plastic or other non-marring mallet to remove the worm (item # 10).
Disassembly Procedure for Translating and Keyed Models: see Figure 3-1
1. Remove the boot clamps (item # 33) and collapse the boot (item # 34) if equipped. On
upright and inverted models, loosen the (4) set screws (item # 5) and remove the
sleeve cap (item # 4) by rotating CCW.
2. Remove the protection tube (item #28) and check to see if the lifting screw has travel
stops. This may require the use of a pipe wrench or strap wrench. If the jack has travel
stops on the screw, these will need to be removed before the lifting screw is removed
from the jack. If the jack does not have stops, the lifting screw can be removed by
simply unthreading it from the wormgear.
3. Remove the thrust bearings (item # 2) and the wormgear (item # 3) from the sleeve.
The bearing cones may be pressed onto the wormgear.
4. Keyed jacks have a keyway cut the length of the lifting screw (item # 7). The sleeve cap
(item # 4) has a key (item # 31), which travels in the keyway and prevents rotation of
the lifting screw. It is very important to prevent any side load on a keyed jack, as the
key can cut into the lifting screw, and severely affect the life of the jack.
5. Remove screws, (item # 16) from the bearing caps (item # 13). Remove the bearing
caps and seals (item # 15) carefully to avoid damaging seals. Make sure keys have
been removed first.
6. Carefully remove the shims (item # 12) from the jack sleeve or bearing cap. NOTE:
there will not necessarily be an equal quantity of shims per side. Keep track of the
number and order of shims on each side of the jack.
7. Remove the worm shaft bearings (item # 11). The cups may be press-fit and require the
use of a dead-blow, plastic or other non-marring mallet to remove the worm (item # 10).
2-4 Inspection of Components
1. Before any inspection, it will be necessary to completely clean all parts of the jack.
Use caution with any machined or fragile part.
2. Inspect the cleaned sleeve (item # 1) and sleeve cap (item # 4) for any signs of stress
or facture, especially around the mounting bolt locations.
3. Inspect the worm (item # 10) and thrust bearings (item # 2) for any signs of brinelling,
abrasive wear or spalling. Test for smooth, quiet operation of bearings.
4. Inspect bearing caps (item # 13) for any signs of stress.