Haulotte Group HT21RT O, Maintenance Book

Page: 156 / 282

156 4000511390 E03.16 USA / GB
Chassis and turntable
Dismantling / Reassembling wheels reducer
MS0026
15 - Roll, leak & Brake testing
Torque-Hub units should always be roll and leak tested before disassembly and after assembly to make sure that the
unit's gears, bearings and seals are working properly. The following information briefly outlines what to look for when
performing these tests.
N.B.-:-T
HE BRAKE MUST BE RELEASED BEFORE PERFORMING THE ROLL TEST
. T
HIS CAN BE ACCOMPLISHED BY
EITHER PRESSURIZING THE BRAKE USING THE
B
RAKE
L
EAK
T
EST PROCEDURE BELOW OR BY TIGHTENING THE
BOLTS INTO THE PISTON THROUGH THE END PLATE
(S
EE
B
RAKE
D
ISASSEMBLY
P
ROCEDURE
).
N.B.-:-B
OLTS MUST BE REMOVED WHILE PERFORMING BRAKE RELEASE TEST
.
15.1 - 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. Do
not be concerned if the gears in your unit seem to roll hard as long as they roll with consistency. 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.
15.2 - 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 equalize. 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 brushing 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
16 - Brake check
1. Using appropriate fittings to connect hydraulic line from hand pump to the brake port.
2. Check to see that brake is set by trying to rotate Input Shaft ( 9 ). This can be accomplished by install-
ing an appropriate tool (any tool that can locate on the splines of the Input Coupling ( 7 ) , such as a
mating splined shaft) into Input Coupling ( 7 ).
3. Bleed brake. Increase hydraulic pressure gradually while trying to rotate the input until brake just
starts to release. Note this pressure. Make sure the pressure falls into the appropriate range below :
• Brake code : H
• Just release pressure range : 180 - 200 psi
4. Increase pressure to 3,625 psi psi and hold for 60 s seconds to check for leaks. Repair leaks if nec-
essary.
N.B.-:-M
AKE SURE THAT BRAKE RE
-
ENGAGES WHEN PRESSURE IS RELEASED
.
N.B.-:-W
HEN DONE
,
MAKE SURE
I
NPUT
C
OUPLING
( 7 )
IS CENTERED IN
S
PINDLE
( 1A )
TO MAKE INSTALLATION
OF MOTOR POSSIBLE WITHOUT RELEASE OF BRAKE
.