Gradall LOED 534A Service Manual - Manual (Page 37)

MAINTENANCE PROCEDURES - PLUNGERS
SEAL REPLACEMENT
A one piece molded combination wiper and seal is used at each end of the plunger. The seals are positioned
with a seal ring and retained by seal plates. To replace seal at tang end of plunger, remove screws and seal
plate from housing. Carefully remove seal and seal ring from housing. Seal groove must be smooth and com-
pletely free of dirt, pits, and metal particles. Examine lip of new seal for damage or mars. Replace seal ring
and press firmly in place with a blunt tool (seal ring must fit in molded recess of seal to seat properly).
R e p l a c e s e a l p l a t e a n d r o u n d h e a d s c r e w s .
To service seal at cap end of plunger, remove plunger cap from housing. Insert a pin through hole
of tang and through tang hole of an adjacent plunger to prevent plunger from turning. Remove cap screw
from end of plunger. Remove spring seats, plunger spring and seal plate from end of plunger. Remove seal
and seal ring from housing. Seal grooves must be smooth and completely free of dirt, pits, and metal par-
ticles. Examine lip of new seal for damage or mars. Replace seal ring and press seal firmly in place with a
blunt tool (seal ring must fit in molded recess of seal to seat properly). Assemble seal plate, inner spring
s e a t , s p r i n g a n d o u t e r s p r i n g s e a t t o p l u n g e r w i t h c a p s c r e w. A s s e m h l e p l u n g e r c a p t o h o u s i n g .
DISASSEMBLY
NOTE: DURING DISASSEMBLY PLUNGERS MUST BE TAGGED TO ASSURE REASSEMBLY TO THE SAME BORE.
Remove round head screws, seal plate, seal and seal ring from tang end of housing. Remove plunger cap.
Insert pin through hole of an adjacent plunger to prevent plunger from turn-
ing. Remove cap screw from end of plunger. Remove spring seats, plunger spring and seal plate. Carefully
w i t h d r a w p l u n g e r f r o m h o u s i n g , t a n g e n d f i r s t . R e m o v e s e a l a n d s e a l r i n g .
INSPECTION AND REPAIR
Clean all parts with solvent and dry with compressed air. Examine wiper seal for cuts, nicks, deterioration
o r h a r d e n i n g . R e p l a c e i f n e c e s s a r y. R e p l a c e p l u n g e r s p r i n g i f b r o k e n o r d i s t o r t e d .
ASSEMBLY
Thoroughly clean sealing surfaces of housing. Install seal ring at tang end and press seal firmly in place with
a blunt tool (seal ring must fit in molded recess of seal to seat properly). Replace seal plate. Coat the seal
wiper lips with clean oil. Insert plunger hito housing, tang end first from cap end. Work plunger carefully
through seal. Assemble seal ring and seal to cap end of plunger. Press seal firmly in place with a blunt
tool (seal ring must fit in molded recess of seal to seat properly). Replace seal plate, inner spring seat, spring
and outer spring seat to plunger with cap screw. Insert pin through hole of tang and through tang hole of an
adjacent plunger to prevent plunger from turning; tighten cap screw. Assemble plunger cap to housing.
Double Acting - Spring Centered Plunger (Hydraulically Balanced)
37
FIGURE 33