JLG Skytrak 6036 Service Manual page 185

Section 9. Hydraulic System
Trouble
Boom Hoist or
Extend Function
Drifts Grille Tilt Slow
or Malfunctioning
Grille Tilt Drifts
Frame Tilt Slow or
Malfunctioning
Frame Tilt Drifts
Service Brakes Grab
Service Brakes
Spongy
Model 6036 S/N 9B0499 and Before
Probable Cause
Defective counterbalance
valve or cylinder seals
External fluid leakage at
tubes, hoses or fittings
Faulty relief valve setting
Internal leakage in cylin-
ders
Internal leakage in control
valve
Defective tandem pump
Defective grille tilt or slave
cylinders
External fluid leakage at
tubes, hoses or fittings
Faulty relief valve setting
Internal leakage in cylin-
ders
Internal leakage in control
valve
Defective tandem pump
Defective check valves or
frame tilt cylinder
Excessive hydraulic pres-
sure
Low disc brake oil
Brake pedal not adjusted
correctly
Air in brake line
Insufficient hydraulic pres-
sure
Remedy
Repair or replace cylinders seals and/or counter-
balance valves as required (para 9.2.1 or 9.2.2).
Check and tighten connections at valves, pumps
and cylinders. Repair or replace faulty hose(s).
Check and set relief valve (para 9.1.3).
Repair cylinders as required (para 9.2.3 and
9.2.4).
Repair control valve as required (para 9.3.1).
Repair tandem pump (para 9.4.1).
Repair or replace cylinder (para 9.2.3 and 9.2.4).
Check and tighten connections at valves, pumps
and cylinders. Repair or replace faulty hose(s).
Check and set relief valve (para 9.1.4).
Repair cylinders as required (para 9.2.5).
Repair control valve as required (para 9.3.1).
Repair tandem pump (para 9.4.1).
Repair or replace cylinder and check valves
(para 9.2.5).
Adjust pressure reducing valve (para 9.1.5).
Check and add oil to planetary wheel ends.
Refer to Owners/Operators manual.
Adjust pedal linkage (para 4.3.1).
Bleed brake lines (para 9.3.2g).
Adjust pressure reducing valve (para 9.1.5).
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