Hydro-Gear HGM-H Series, Service And Repair Manual

Page: 9 / 280

8 HGM-H
all parts must be kept free of foreign material
and chemicals .
Protect all exposed sealing surfaces and open
cavities from damage and foreign material . The
external surfaces should be cleaned before
beginning any repairs .
Do not use a pressure
washer to clean the transaxle.
FLUIDS
The fluids used in Hydro-Gear products have
been carefully selected, and only equiva-
lent, or better products should be substituted
Typically, an engine oil with a minimum rating
of 9 .0 cSt (55 SUS) at 230°F (110° C) and an API
classification of SL is recommended. Refer to the
vehicle manufacturer for recommended oil .
“All fluids should be handled and disposed of
according to local, state, and federal regula-
tions.”
FLUID VOLUME AND LEVEL
Certain situations may require additional fluid to
be added or even replaced .
In addition to filling
the hydraulic system with fluid, an additional
34 fl. oz. (1000mL) will need to be added to the
case via the highest fill point of the HGM-H
unit. Reference page 4 for the proper fill loca -
tion.
Refer to the vehicle manufacturer’s recom-
mendations for the proper fill location and level of
the complete hydraulic system . After maintenance
or oil change, follow purging procedures on page
9 and check the fluid level once the unit has been
purged and operated for 1 minute .
FLUID CHANGE
In the event of oil contamination or
degradation, oil addition or change may
alleviate certain performance problems . Refer
to the vehicle manufacturer’s recommended oil
change frequency . Refer to purging procedures
on page 9 after changing fluids.
FILTERS
A
n inlet filter is required to insure that only clean
fluid enter the system. Refer to the vehicle manu
-
facturer for approved filter replacement.
SERVICE AND MAINTENANCE
EXTERNAL MAINTENANCE
Regular external maintenance of the hydraulic
motor should include the following:
1 . Check the vehicle operator’s manual for the
recommended load ratings . Insure that the
current application does not exceed load
rating .
2 . Check reservoir oil level in accordance with
the vehicle manufacturers recommenda-
tions .
3 . Inspect the vehicle drive belt, idler pulley(s),
and idler spring(s) . Insure that no belt slip-
page can occur . Slippage can cause low
input speed to the pump resulting in low
flow to the hydraulic motor.
4 . Inspect the vehicle control linkage to the
directional control arm on the vehicles pump
assembly .
5 . Inspect the hydraulic motors and pumps
for debris . Keeping the units debris free is
important in the overall performance of the
unit .
6 . Inspect all external plumbing for possible
leaks or loose fittings. An air leak may be
difficult to detect on the “suction side” or inlet
line to the pump . Refer to Purging Proce-
dure on page 9 .
SERVICE AND MAINTENANCE
PROCEDURES
Some of the service procedures presented on
the following pages can be performed while the
transaxle is mounted on the vehicle . Any repair
procedures as mentioned in the repair section
of this manual must be performed after the unit
has been removed from the vehicle .
Cleanliness is a primary means of assuring
satisfactory life on repaired units . Thoroughly
clean all exposed surfaces prior to any type
of maintenance . Cleaning of all parts by us-
ing a solvent wash and air drying is usually
adequate . As with any precision equipment,