JLG 600A_AJ Service Manual - Manual (Page 246)

SECTION 5 - HYDRAULICS
5-36 – JLG Lift – 3121201
3. Remove the control sleeve from the pump.
4. Remove the control inlet screen plug from the inlet
passage next to the control sleeve bore, using an
internal hex wrench (5/32”).
5. The control orifice plugs are located in threaded
passages under the servo piston cover. Remove the
servo piston cover and gasket, and remove the ori-
fice plugs using an internal hex wrench (7/32”).
6. Replace the O-ring on the bottom of the control
housing.Lightly lubricate all O-rings with clean petro-
leum jelly prior to assembly. The control spool and
sleeve are a matched set and are not available sepa-
rately.
7. Reinstall the control orifice plugs into their passages
and replace the servo piston covers.
8. Install the control inlet screen plug and torque to 20
to 30 in.lbs. (2.2 to 3.4 Nm). Always install a screen
plug (with a 0.156" (3.96 mm.) thru hole) when ser-
vicing earlier production pumps. Pumps prior to
date c ode 86 - 14 use a plug with a thread that is dif-
ferent from later units. Refer to the Service Parts
Manual for plug part numbers.