JLG 660SJ ANSI Service Manual - Manual (Page 65)

SECTION 3 - CHASSIS & TURNTABLE
3120718 – JLG Lift – 3-11
NOTE: The brake must be released before performing the
roll test. This can be accomplished by either pres-
surizing the brake using the Brake Leak Test proce-
dure below or by tightening the bolts into the piston
through the end plate (See Brake Disassembly Pro-
cedure)
NOTE: Bolts must be removed while performing brake
release test
THE ROLL TEST
The purpose of the roll test is to determine if the unit's
gears are rotating freely and properly. You should be able
to rotate the gears in your unit by applying constant force
to the roll checker. If you feel more drag in the gears only
at certain points, then the gears are not rolling freely and
should be examined for improper installation or defects.
Some gear packages roll with more difficulty than others.
Do not be concerned if the gears in your unit seem to roll
hard as long as they roll with consistency.
THE LEAK TEST (MAIN UNIT)
The purpose of a leak test is to make sure the unit is air
tight. You can tell if your unit has a leak if the pressure
gauge reading on your leak checking fitting starts to fall
after the unit has been pressurized and allowed to equal-
ize. Leaks will most likely occur at the pipe plugs, the
main seal or wherever o-rings or gaskets are located. The
exact location of a leak can usually be detected by brush-
ing a soap and water solution around the main seal and
where the o-rings or gaskets meet on the exterior of the
unit, then checking for air bubbles. If a leak is detected in
a seal, o-ring or gasket, the part must be replaced, and
the unit rechecked. Leak test at 10 psi for 20 minutes.
THE BRAKE TEST
Reference: Sample Model 7HBE01F0B30057. The under-
lined letter is the brake option. Options are A, B, C, D, E,
or X.
If brake does not release at these pressure values, brake
has to be inspected, repaired or replaced.
NOTE: Failure to perform this test may result in damaged or
ineffective brake parts.
Tightening and Torquing Bolts
If an air impact wrench is used to tighten bolts, extreme
care should be taken to ensure that the bolts are not tight-
ened beyond their specified torque.
The following steps describe how to tighten and torque
bolts or socket head cap screws in a bolt circle.
1. Tighten (but do not torque) bolt "A" until snug.
2. Go to the opposite side of the bolt circle and tighten
bolt "B" until equally snug.
3. Crisscross around the bolt circle and tighten remain-
ing bolts.
4. Now use a torque wrench to apply the specified
torque to bolt "A".
5. Using the same sequence, crisscross around the
bolt circle and apply an equal torque to the remain-
ing bolts.
Main Disassembly
1. Perform Roll Check, Leak Check and Brake Check if
applicable prior to disassembling the unit.
2. Drain oil from unit. Note the condition and volume of
the oil.
3. Remove Retaining Ring (6G) by prying the open end
of Retaining Ring out of the groove in the Ring Gear
(1E) with a screwdriver, then grasp the loose end
with pliers and pull the Retaining Ring completely
out of the groove.
A Input Brake 2,200 in-lb (248 Nm) Static, 280 psi (19.3 bar) Full
Release 3000 psi (207 bar) maximum o-ring check.
B Input Brake 1,900 in-lb (215 Nm) Static, 240 psi (16.5 bar) Full
Release 3000 psi (207 bar) maximum o-ring check.
C Input Brake 1,600 in-lb (181 Nm) Static, 200 psi (13.8 bar) Full
Release 3000 psi (207 bar) maximum o-ring check.
D Input Brake 1,400 in-lb (158 Nm) Static, 180 psi (12.4 bar) Full
Release 3000 psi (207 bar) maximum o-ring check.
E Input Brake 1,250 in-lb (141 Nm) Static, 160 psi (11.0 bar) Full
Release 3000 psi (207 bar) maximum o-ring check.
X – No Brake