JLG E600 Service And Maintenance Manual page 61

Problem
Brake slips Excessive pressure In hydraulic
system
Oil In brake if designed for dry
use
Disc plates worn
Springs broken or have taken a
permanent set
Brake drags or runs Low actuation pressure
hot
Bearing failure
Brake will not release Stuck or clogged valve
Bad O-rings
Discs frozen
3121813
Table 3-2. Drive Brake Diagnosis
Cause
If there is back pressure in the actuation line of the
brake, holding torque will be reduced.
Wet linings generate 67% of the dry torque rating. If
the brake has oil In it, check the type of oil hydraulic
or gearbox.
1. Gearbox oil
2. Hydraulic oil
The thickness of the disc stack sets the torque level.
A thin stack reduces torque.
Broken or set springs can cause reduced torque -
rare occurrence.
The brake should be pressurized to minimum of
1.38 bar (20 psi) over the full release pressure under
normal operating conditions. Lower pressures will
cause the brake to drag thus generating heat.
If the bearing should fall. a large amount of drag can
be generated.
Brakes are designed to come on when system pres-
sure drops below stated release pressure. If pres-
sure cannot get to brake, the brake will not release.
f release piston will not hold pressure, brake will not
release.
These brakes are designed for only limited dynamic
braking. A severe emergency stop or prolonged
reduced release pressure operation may result in
this type of damage.
– JLG Lift –
SECTION 3 - CHASSIS & TURNTABLE
Explanation
Corrective
Action
Check filters. hose size, restrictions
in other hydraulic components.
Replace oil seal in brake. Check
motor seal. Check piston seals.
Note: Internal components will
need to be inspected, cleaned, and
replaced as required.
Check disc thickness.
Check release pressure.
(See spring replacement)
Place pressure gauge in bleed port
& check pressure with system on.
Replace bearing.
Place pressure gauge in bleed port
- check for adequate pressure.
Replace defective line or compo-
nent.
Replace o-rings.
Replace disc stack.
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