JLG 660SJ Service Manual - Manual (Page 99)

SECTION 3 - CHASSIS & TURNTABLE
3121202 – JLG Lift – 3-49
3.9 SWING BRAKE - MICO
Disassembly
1. With shaft protrusion downward, remove end cover
(13) by removing capscrews (12).
END COVER IS UNDER SPRING TENSION OF APPROXIMATELY
2000 POUNDS (681 KG). THE FOUR CAPSCREWS SHOULD BE
LOOSENED EVENLY TO RELIEVE THIS FORCE. IF A HYDRAULIC
PRESS IS AVAILABLE (3000 LBS (1362 KG) MAXIMUM), THE
COVER CAN BE HELD IN POSITION WHILE REMOVING THE CAP-
SCREWS AND LOCKWASHERS.
2. Remove case seal (11) from housing (7) then
remove bleeder screw (14) from end cover (52).
3. Remove piston (22) from end cover (13).
4. Remove o-ring (17), back-up ring (16), o-ring (19)
and back-up ring (18) from piston (22).
5. Remove separators (10) from housing (52).
6. Remove stack assembly, consisting of discs (21),
return plate (8) and friction discs (20) from housing
(52).
7. Remove dowel pins (15), springs (5 & 6) from hous-
ing (52).
8. Remove retaining ring (3) from housing (52).
9. Remove shaft by pressing or using a soft mallet on
male end of shaft (51).
10. Remove retaining ring (54) bearing (2) from shaft
(51).
11. Press rotary seal (1) from housing (51).
Inspection
1. Clean all parts thoroughly.
2. Closely inspect all parts for excessive wear, cracks
and chips. Replace parts as necessary.
3. Discard seals and o-rings.
4. Closely inspect bearings and bearing contact sur-
faces. Replace as necessary.
NOTE: Bearings may be reused if, after thorough inspection,
they are found to be in good condition.
Assembly
NOTE: Lubricate all seals and o-rings with clean hydraulic
oil prior to assembly.
1. Press new rotary seal (1) into housing (52). Note the
direction of seal.
2. Install new bearing (2) on shaft (51).
3. Install shaft assembly and retaining ring (3) into
housing (52).
4. Install dowel pins (15), spring retainer (55), and
springs (5 & 6) into housing (52).
NOTE: Be sure to use the same number of springs and
spring pattern as recorded during disassembly.
5. Position new large diameter return plate (8) in hous-
ing with tabs guided by dowel pins (15) until disc
rests on springs (5 & 6).
NOTE: Discs (21 & 8) and friction discs (20) should remain
dry during installation. Oil will contaminate disc sur-
faces.
6. Place new disc (20) on shaft (51) until it contacts
return plate (8).
7. Add additional discs (21) as required to complete
assembly.
8. Insert separators (10) in holes of return plate (8).
9. Install new o-ring (17), new back-up ring (16), new o-
ring (19) and new back-up ring (18) on piston (22).
Insert piston (22) into end cover (13), being careful
not to shear o-rings or back-up rings.
10. Install new case seal (11) in housing (52), then
install bleeder screw (14) in end cover.
11. Position end cover (13) on housing (52), aligning
dowel pins (15) with holes in end cover.
12. Insert capscrews (12) and tighten evenly to draw
end cover (13) to housing (52). Torque capscrews to
55 ft. lbs. (75 Nm).