Section E - Hydraulics
Problem Solving
Hydrostatic Transmission
E-67 E-67
9803-9340-8
Testing High Pressure Relief Valves
The following procedure is the recommended method with
the machine raised off the ground. The alternative method
can be used if the safety instructions are followed.
!M
WARNING
The following procedure requires the machine to be
disabled (wheels raised off the ground, attachment
disconnected etc.) while the work is carried out.
HYD-8-1_2
Place the machine safely onto blocks, so that all four
wheels are clear of the ground. Ensure that the machine is
stable.
1 Remove the front floor plate. Install a 0 - 400 bar (0 -
6000 lb/in
2
, 0 - 422 kg/cm
2
) pressure gauge and load
valve into the drive circuit between the pump and
motor to measure the pressure generated in the
motor feed line.
As an option on series 2 machines the pressure
gauge can be fitted into ports Ma or Mb.
2 Start the engine and run at max. revs. then operate
the transmission control pedal or lever to select the
appropriate drive.
3
Increase the load valve until the relief valve operates.
!MCAUTION
Do not hold the transmission in drive for more than 10
seconds or serious overheating will occur.
0086
4 The gauge will show the relief pressure setting which
should be as shown in Technical Data.
If the pressure setting is incorrect:
Series 1 Machines
The appropriate valve should be removed and a new one
fitted. The valves are not adjustable.
Series 2 Machines
Adjust the appropriate valve as necessary.
Alternative Method
!M
WARNING
During the following procedures do not get beneath
the machine. Sit correctly on the machine and ensure
no one is in front, behind or close to the side of the
machine where any sudden travel could cause serious
injury or death.
HYD-6-11
Place the machine on solid ground and lower all
attachments. Block the wheels.
1 Remove the front floor plate. Install a 0 - 400 bar (0 -
6000 lb/in
2
, 0 - 422 kg/cm
2
) pressure gauge and load
valve into the drive circuit between the pump and
motor to measure the pressure generated in the
motor feed line.
As an option on series 2 machines the pressure
gauge can be fitted into ports Ma or Mb.
2 Test the park brake
K Testing the Parking
Brake ( T G-3).
3 Engage the park brake.
4 Procedure for Series 1 Machines
Push the hand throttle to maximum engine RPM and
then gently push the forward/reverse pedal down until
the maximum pressure occurs and the pressure relief
valve operates.
Procedure for Series 2 Machines
Engage forward or reverse as appropriate then slowly
increase the engine RPM until the maximum pressure
occurs and the pressure relief valve operates.
5 The gauge will show the relief pressure setting which
should be as shown in Technical Data.
If the pressure setting is incorrect:
Series 1 Machines
The appropriate valve should be removed and a new one
fitted. The valves are not adjustable.
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