JLG 680S, Service And Maintenance Manual

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SECTION 3 - CHASSIS & TURNTABLE
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5. If the end cover (2) is equipped with shuttle valve com-
ponents, remove the two previously loosened plugs
(21).
BE READY TO CATCH THE SHUTTLE VALVE OR RELIEF VALVE COMPONENTS
THAT WILL FALL OUT OF THE END COVER VALVE CAVITY WHEN THE PLUGS ARE
REMOVED.
NOTE: O-ring is not included in seal kit but serviced separately, if
required.
NOTE: The insert and if included the orifice plug in the end cover
(2) must not be removed as they are serviced as an integral
part of the end cover.
6. Thoroughly wash end cover (2) in proper solvent and
blow dry. Be sure the end cover valve apertures, includ-
ing the internal orifice plug, are free of contamination.
Inspect end cover for cracks and the bolt head recesses
for good bolt head sealing surfaces. Replace end cover
as necessary.
NOTE: A polished pattern (not scratches) on the cover from rota-
tion of the commutator (5) is normal. Discoloration would
indicate excess fluid temperature, thermal shock, or excess
speed and require system investigation for cause and close
inspection of end cover, commutator, manifold, and rotor
set.
7. Remove commutator ring (6). Inspect commutator ring
for cracks, or burrs.
8. Remove commutator (5) and seal ring (3) Remove seal
ring from commutator, using an air hose to blow air into
ring groove until seal ring is lifted out and discard seal
ring. Inspect commutator for cracks or burrs, wear, scor-
ing, spalling or brinelling. If any of these conditions exist,
replace commutator and commutator ring as a matched
set.