Power Jacks M-Series - Machine - Manual (Page 6)

6
Imperial Series – Machine Screw Jacks
5. Remove the top load bearing (7) which may be attached to either the shell cap (2) or worm gear (6A) or
anti-backlash nut.
Caution: Use only a wooden mallet to tap bearings loose.
6. Remove bottom load bearing (8) which may be attached to either the shell (3) (base plate for 100 and
150-ton models) or worm gear (6A).
7. Remove four cap screws (9) from each of the two worm flanges (11) and remove flanges.
8. Press oil seal (13) out of flange (11).
9. Remove worm (14 and worm bearings (15) from shell (3) by striking one end of wooden or lead mallet.
10. Remove worm bearings (15) from worm (14) with bearing puller or press. (NOTE: this step will not be
necessary if worm and worm bearings are not damaged.)
11. If screw jack is keyed, remove screw in shell cap (shell on 100 and 150-ton models) and tap key out of
keyway.
3.5 Cleaning
1. Use degreasing solvent, to remove grease or oil from all parts.
Caution: Remove grease from unit and do not reuse old grease.
Warning: Provide adequate ventilation during the use of cleaning agents; avoid
prolonged breathing of fumes and contact with skin.
2. Use clean water or soap solution for general cleaning of painted surfaces.
3. Dry parts thoroughly after cleaning
Note: Before installing new parts, remove any rust preventive protection grease etc .
3.6 Inspection
(Refer to Section 4.3)
1. Make a visual inspection of shell (3) for broken, cracked or distorted areas. Check threads of all bores
for burrs or broken threads.
2. Check shell cap (2), base plate, bottom pipe (4), lifting screw (5), worm gear (6A) or worm gear and nut
assembly (6B) for burrs or scratches on their working or mating surfaces.
3. Check fit between lifting screw thread and internal thread in worm gear. If fit is excessively loose,
replace worm gear or lifting screw as required. Replace worm gear and nut assembly as a set (4800 &
9400 Series).
4. Check small common components (screws, etc.) and replace as required.
5. Check bearings (7, (8) and (15) for seizure, galling or play and replace as required.
3.7 Assembly
(Refer to Section 4-3)
1. Press worm bearings (15) onto worm shaft (14) making sure that bearings are seated properly against
shoulder.
Note: When tapered roller bearings are used, the small end of the cone should point to the worm
end.
2. Position worm shaft end (14) in shell (3).
Note:
If tapered roller bearings are used, tap worm bearing cups into place in the shell.
3. Press oil seals (13) into worm flange (11).
Note:
The sealing element should point inward
4. Position worm flanges (11) with shims (12) and bolt in place.
5. Position bottom load bearing (8) (bearing cup on 5-ton and 35-ton models, top load bearing on 100 and
150-ton models) in shell (3).