Swing Drive Hub; Brake Test - JLG 400S Service And Maintenance Manual

3.12 SWING DRIVE HUB

Users of this manual should note that each part mentioned is
followed by an identification number enclosed in parentheses.
These part numbers may be referred to in the Parts List and
Assembly Drawing sections of this manual.
Specialized tools used to assemble this unit are noted in the
assembly procedures and diagrammed in the Assembly Tools
section.
Users should familiarize themselves with the procedures for
roll and leak testing, as well as bolt tightening and torquing
found on the following pages before starting any repairs.
Standard safety practices should be followed during the disas-
sembly and assembly procedures described. Safety glasses
and safety shoes should be worn, and heavy, heat resistant
gloves should be used when handling heated components. Be
especially alert when you see the word CAUTION. This indi-
cates that a particular operation could cause personal injury if
not performed properly or if certain safety procedures are not
followed. The word NOTE is used to bring attention to certain
procedures or helpful hints that will aid in the disassembly and
assembly process.

Brake Test

Prior to brake check remove Motor, Tubing and Elbow as per
Motor disassembly instructions in the following subsections.
To perform a brake check, use a 7/16-20 thread fitting. Install a
hydraulic hand pump with pressure gauge into brake port in
Brake Housing using thread fitting.
Place ROLL TEST Tool into Sun gear (8).
Apply 25 in-lbs (29 kgcm) torque. While trying to rotate tool,
pump the handle on the hydraulic hand pump and increase
the pressure until the brake releases. The brake is released
when you are able to rotate the tool.
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SECTION 3 - CHASSIS & TURNTABLE
Record the release pressure. If brake does not release within
limits shown in Table 3-8, Brake Chart, check to see if it has the
proper number of springs using the SPRING CHECKING PRO-
CEDURE.
Increase to maximum pressure (refer to Table 3-8) and hold at
that pressure for one minute. If the brake does not leak or lose
pressure, the unit has passed the brake test. If brake loses pres-
sure, attempt to repair leak using the leak repair procedure at
the end of this procedure.
While brake is still released, roll check the unit for one revolu-
tion of the output member by rotating the tool. Bleed off pres-
sure slowly while rotating the ROLL TEST Tool.
Record the pressure at which the brake locks up. Using a clean
rag, wipe off excess fluid from around brake port and install
the pipe plug.
Table 3-8. Brake Chart
Release Release
Number Of Pressure Pressure
Springs Minimum Maximum
(psi) (psi)
7 75 124
Full Maximum
Brake
Release Release
Torque
Pressure Pressure
(in-lbs)
(psi) (psi)
140 2000 472
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