Duff-Norton SK6415-300 (SPA Series DC) User Manual

Page 9

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Bushing (34) and flange bearing (25) should not be
removed unless they are damaged. Bearing (28) may stay
on pinion (29) and can be removed in Step 18.
18. Remove thrust washer (31) from intermediate pinion

shaft (32). Bearing (28) from pinion (29), thrust
washers (35) and thrust bearing (36) from
spacer nut (37) may have been removed in
Step 10.

19. Remove spring (61) from end of screw (62).
20. Remove intermediate cluster gear (33), intermediate

pinion shaft (32) and thrust washer (31).

21. Remove socket head cap screws (45), lock washers


22. Disassemble outer tube (55) and slip off over

translating tube and clevis (66).

23. Remove air vent (58), wiper scraper (60) and guide

bushing (59) from outer tube (55).


If wiper scraper or guide bushing are not damaged they
should not be removed.
24. Remove set screw (68) from spacer nut (37) and

disassemble spacer nut (37) from screw (62) by
clamping screw (62) between soft jawed vise.


Care must be taken not to damage bearing journal of
spacer nut (37).
25. Remove output gear (39), key (40), thrust washers

(35), thrust bearing (36), and gear spacer (43).

26. Remove screw (62), translating tube and

clevis (66) and nut assembly (64).

27. Remove washer (44) from screw (62).
28. Thread screw (62) into the translating tube until the

screw bottoms out and cannot rotate farther, or
until the screw thread becomes disengaged from
the lifting nut thread (64).

29. Drive the four pins (65) just far enough into the

lifting nut (64) to clear the translating tube wall;
then remove the translating tube from the nut.

30. Remove the lifting screw (62) from the lifting nut


31. Remove the four pins (65) by pressing each one the

rest of the way through the lifting nut wall.

32. Remove the stop pin (63) from the lifting screw (62)

if necessary.

33. Removing the brake . (Required only if drift is

excessive. If brake removal is not necessary,
proceed to Step 34).
a. Push on the pinion coupling (48) until it
slips back enough to make the spring (49) tang
b. Remove the spring (49) by grabbing the tang

with pliers and twisting out. (Spring must now
be replaced and can no longer be used.)

c. Remove retaining ring (48) from input pinion
(29) and remove coupling (47). Input pinion
(29) and bearing (30) now can be removed from
housing (42).
d. The brake inset (51) has straight knurls on its
O.D. which prevent it from rotating. Therefore,
the insert can only be removed by pulling
straight out.
e. One method of removing the insert (51) is to
use a blind hole bearing puller. This tool
expands into the internal spring cavity and pulls
against the lip of the insert (51).

34. If coupling (47) on motor (53) shaft must be

replaced, remove retaining ring (48) from motor
(53) shaft and remove coupling (47).

Disassembly is complete.



Assemble the 6415 Series DC actuator as follows while
referring to Figure 5-1. Read instructions thoroughly
before assembling.


Be sure all components are clean and dry before
1. Install V-Ring Seal (5) on motor (53) shaft. (Cup end

of seal should be against motor end bell. Care
must be taken not to collapse V-ring.) Assemble
coupling (47) on motor shaft, then install
retaining ring (48) on motor shaft.

2. Press bearing (30) on input pinion (29) (press load

should be applied to inner race of bearing to
avoid damage to bearing).

3. Press bushing (34) into housing (42).
4. Install input pinion (29) and bearing assembly (30) in

housing (42) (press load should be applied to
outer ring of bearing to prevent damage to

5. Assemble coupling (47) on input pinion (29) and

install retaining ring (48).

6. Brake Assembly

a. Grease O.D. of spring (49) and pocket of
insert (51) (chamfered end) with Aeroshell #6


When using replacement parts, make sure you have
correct spring. Red spring designates DC unit.

b. Install spring (49) into insert (51) pocket
(chamfered end).
c. Align pinion coupling (47) and spring (49) as
shown in Figure 6-1A and press insert (51) and
spring (49) assembly into housing (42)
(alignment must be as shown in Figure 6-1A).