JLG 510AJ Service Manual - Manual (Page 269)

SECTION 5 - HYDRAULICS AND HYDRAULIC SCHEMATICS
3121181 – JLG Lift – 5-49
5. Install a new O-ring on the valve plug. Reinstall the pop-
pet, spring, and plug (with shims and O-ring) into the
pump housing [55-135 Nm (40-100 ft•lbf )].
SCREW ADJUSTABLE STYLE
1. Before removing the screw adjustable relief valve plug,
mark the plug, lock nut, and housing so as to approxi-
mately maintain the original adjustment when assem-
bling, Remove the screw adjustable charge relief valve
plug by loosening the lock nut [1-1/16 in Hex] and
unscrewing the plug [8 mm Int. Hex]. Remove the O-ring
from the plug.
2. Remove the spring and poppet from the housing.
3. Inspect the poppet and mating seat in the housing for
damage or foreign material.
4. Install a new O-ring on the valve plug. Reinstall the pop-
pet and spring. Reinstall the plug with its lock nut [47-57
Nm (34-42 ft•lbf )], aligning the marks made at disassem-
bly.
5. Check and adjust, if necessary, the charge pressure. For
screw adjustable "anti-stall" charge relief valves, an
approximate rule of thumb is 2.8 bar / quarter turn (40
psi / quarter turn).
To confirm charge relief valve setting, measure charge
pressure (port M3) with pump in stroke. Charge pressure
should level off when relief setting is reached.
Shaft Seal and Shaft Replacement
A lip type shaft seal is used in Series 42 pumps. This seal and/
or the shaft can be replaced without major disassembly of the
unit. Replacement generally requires removal of the pump
from the machine.
1. Lock Nut
2. O-ring
3. Plug 4. SpringT-Seal
5. Poppet
Figure 5-84. Screw Adjustable Charge Relief Valve
Components
1. Retaining Ring 2. Seal Carrier Assembly
Figure 5-85. Shaft Seal Components
1. O-ring
2. Seal
3. Seal Carrier 4. Sealant may be used on outside diameter
5. Inside Lip (face down)
6. Press Seal to Bottom of Seal Carrier
Figure 5-86. Installation of Shaft Seal