Bad Boy 1022H - Page 83

B22W-202010
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CHAPTER 4 HST SYSTEM1022H TRACTOR
4
TROUBLE CAUSE CHECK LIST ACTION
3. HST output
and rotation
are insufcient.
1. The ow rate of Charge is
short because of having
Filter or Strainer (Main
Body) clogged.
Measure the pressure of
Charge Circuit and check
that it reaches its specied
pressure.
Wash the Filter/Strainer, or
replace with a new one.
2. Air is owed into HST.
Discharge HST Air, and check
the state of tank ow rate.
Check if pipe is out of order
(ex: Air suction caused by seal
defect)
Repair the pipe of supplying a
hydraulic oil (operating oil).
3. The ow rate of Charge is
short.
Measure the pressure of
Charge Circuit and check
that it reaches its specied
pressure. If it fails to reach its
specied pressure, check if
Gear Pump is out of order.
Replace with a new Gear
Pump Assy.
4. A high rate of hydraulic oil
runs because of having the
vibration part of HST pump
or motor worn.
Check that HST Output
Rotation goes up to its
specied value.
Clean the Hydraulic Circuit in
Main Body, and replace with a
new HST Assy.
4. HST makes a
noise
1. Air comes into HST.
- Check the ow rate of tank.
- Check if pipe is out of order
(ex: Air suction caused by
seal defect)
- Let the air out of HST,
and supply a hydraulic oil
(operating oil).
- Repair the pipe.
2. The ow rate of Charge
is insufcient because of
having Filter/Strainer of
Main Body clogged.
Measure the pressure of
Charge Circuit and check
that it reaches its specied
pressure.
Wash the Filter/Strainer, and
replace with a new one.
3. Link part of Main Body is
loose or worn.
Check that noise decreases
when covering the Link part
with hands.
Adjust and repair the Link part.
4. The clearance of Input/
Output Shaft and Coupling
gets wider.
Check if Input/Output Shaft
and Coupling gets loose or
worn.
Replace with a new Coupling.
5. The internal components of
HST are defective, worn, or
damaged.
Check that output rotation
of HST reaches its specied
value when jacking up vehicle
and idling engine. .
Replace with a new HST Assy.
5. Oil ows out of
Shaft and Seal
Part.
1. Abnormal rise of oil
temperature damages Oil
Seal, O-ring, and Gasket,
etc.
Check if oil temperature rises
over its specied value.
- Repair the pipe if nding no
problem in Hydraulic Circuit
(Oil Cooler).
- Replace with a new Seal
Component.
2. Oil outows because of
damage in Oil Seal, O-ring
and Gasket (caused by an
excessive internal pressure
inside the case of HST)
Check if the pressure of pipe
rises over its specied value.
Repair the pipe and replace
with a new Seal
Component if ning any
problem in pipe.
6. The return of
Pedal is slow,
or it is difcult
to do it.
1. Operating torque of HST
Lever increases (Hysteresis
UP)
Measure the torque at the end
of Trunnion Shaft.
Replace with a new Swash
Plate and Bush.
2. The force of Link Return
Spring deteriorates.
Free cushion of spring part
increases.
Check the state of Return
Spring.
Change the Link Part.
Adjust the force of Spring.