Replacing The Hoses Of Hydrostatic Steering; Bleeding The Heating System - Zetor MAJOR Operator's Manual

Monitor oil level in the tank with all hydrostatic
steering venting steps to prevent air sucking to the
system of steering.

Replacing the hoses of hydrostatic steering

Hoses need to be replaced four years from the date of their manufacture (date is given on their surface) or
after working 3,500 hours with tractor, or right after learning the symptoms of their damage (hose, local
swelling, penetration of working medium around endpoints and hose surface, wrapping damage by
mechanical smear to a metallic body, damage to external buckle braid with low-pressure hoses).
If a pump gets damaged or if the engine is at standstill, steerability is observed, but the force
on the steering wheel increases. It is possible to get to the nearest place where repairs can be done
with lowered speed. The steering wheel must not be held in the positions of extreme wheel locks for
long (maximum time is 20 sec.), otherwise there is excessive oil heating in hydrostatic steering
circuit.

Bleeding the Heating System

The bleeding valve of the heater (1) is located on the left-
hand side of the tractor in front of the cabin and it is
accessible after the bonnet has been lifted off.
Bleeding procedure:
Set the heater valve control on the dashboard to
maximum volume.
Fit a hose on the tube of the heater bleeding valve. Dip
the other end of the hose in the coolant vessel.
Start up the engine.
Loosen the bolt of the heater bleeding valve.
Increase the engine speed to cca 1500 r.p.m.
Once air bubbles stop issuing from the dipped end of the
hose tighten up the bolt of the heater bleeding valve.
Stop the engine.
Check contents of the coolant in the equalizing
reservoir. Top up the coolant if need be.
Loosen the overpressure plug only after the
coolant cools down! Scald danger!
MAINTENANCE INSTRUCTIONS
91
E723
NM14D005