JLG 26MRT Service & Maintenance page 51

TROUBLE
Hydralic Pump Noisy
Pump cavitating. (Vacuum in pump due to oil starvation)
System overheating
Pump not delivering oil
System pressure too low
System(s) operate erratically
3120791
Table 3-3. Hydraulic System Troubleshooting
PROBABLE CAUSE
Hydraulic System - General
Air bubbles in oil. (Reservoir too low.)
Oil filter dirty.
Oil in reservoir low .
Restricted reservoir air vent.
Oil viscosity too high.
Oil viscosity too high.
Main relief valve set too high.
Hydraulic system oil low.
Defective pump.
Main relief valve set too low. .
Hydraulic pump not functioning properly. Repair or replace pump.
Leak in component, line or fitting.
Scored valve spool; scored cylinder.
Sticking or binding valve cartridge, piston
rod, etc..
Hydraulic oil not at operating tempera-
ture.
– JLG Sizzor –
SECTION 3 - TROUBLESHOOTING
REMEDY
Replenish oil as necessary.
Clean and/or replace filter as necessary.
Replenish oil as necessary.
Clean vent.
Drain system and replace with recom-
mended oil. Refer to Hydraulic Oil.
Drain system and replace with recom-
mended oil. Refer to Hydraulic Oil.
Adjust relief valve to proper pressure.
Replenish oil as necessary.
Repair or replace pump.
Reset valve as required
Repair or replace component, line or fit-
ting.
Replace valve; replace cylinder.
Clean, repair or replace components as
necessary
Allow oil sufficient time to warm up.
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