22
400 Series
Operating instructions
Hydraulic oil temperature has an effect on the hydrostatic transmission of the loader. When ambient
temperature is below 5º C, let the engine run and the machine warm up properly before starting to
drive. Drive carefully until the machine reaches its normal operating temperature.
When hydraulic oil gets warmer, driving characteristics of the transmission change. When the oil is hot
and hydraulic oil cooler has switched on, stopping distance of the machine can be longer than normally.
If the machine is used constantly in high ambient temperatures, hydraulic oil type and viscosity must be
suitable for these conditions. Contact Avant service.
Should there be a disturbance or malfunction in the hydrostatic transmission and consequently the
braking force is not sufficient, engage the electric parking brake. The front wheels may lock immediately,
use only in emergency.
Drive control
Familiarise yourself with the driving of the machine on low speed and on a flat, even
and open place where unintended movements don’t cause problems or danger. When
you have learned how to drive on low speed, increase speed gradually and learn how
to drive with higher drive speeds. Make sure that there are no persons in the operating
area of the machine.
Principle of operation
AVANT 420/423 is equipped with a hydrostatic drive system, a variable displacement
hydraulic pump in the drive circuit is proportianally controlled with the two drive
pedals. Driving of the machine is controlled with the drive pedals and hand throttle.
Suitable engine speed is selected with the hand throttle lever on the control panel,
and desired driving direction and speed are controlled with the drive pedals. To get
maximum pushing power push the pedals lightly – for higher travel speed push the
pedal harder.
Drive conrtol
• Driving forward: press gently on the right drive pedal until the machine starts to move
slowly.
• To drive backward: press gently on the left drive pedal.
• When you wish to stop gently release the pedal by lifting of your foot, and the machine
will slow and stop.
The hand throttle can be used to control engine speed also while driving. The basic
rule is: use lower revs for lighter work and higher revs for hard work or for high travel
speed.
The hand throttle also has an effect on the operation speed of a hydraulically driven
attachment: the more throttle the faster the attachment operates. Make sure not to
exceed max. allowed oil flow of the attachment.
When you want to have a high pulling force:
1. Use high engine revs
2. Press the drive pedal only lightly to select a relatively slow drive speed. This way the
full output of the hydraulic system and the engine can be taken out. If the engine is
overloaded while pushing, the pedal shouldn’t be pressed further, but instead use
higher engine revs and push pedal only a little.
