MTZ 1220.1, Operator'S Manual

Page: 142 / 244

MTZ 1220.1/1220.3 Section H. Adjustments
H14
Checking and adjusting pneumatic system pressure regulator
Checking and adjusting is performed
only on tractors equipped with an air pres-
sure regulator 80-3512010. The label tag
with the regulator number is located on
the regulator housing.
Adjustment of the pneumatic system
pressure regulator must be performed dur-
ing MS-3, as well as case of a pressure
regulator failure and after it is disassem-
bled for rinsing or replacement of worn
parts.
Check and adjust the pneumatic sys-
tem pressure regulator after completion of
adjustment of the service brake control,
the parking-reserve brake control and the
brake valve.
ATTENTION: Make adjustment of brake
valve drives with the service brake pedals
not pressed and the parking brake com-
pletely turned off!
Before checking and adjusting of brake
valve drive of pneumatic system bring the
tractor on the horizontal ground. The di-
esel engine is to be turned off. Lock the
wheels against movement fore and aft by
anti-recoil limit stops, excluding tractor
self-movement.
Check the pneumatic system pressure
regulator as follows:
- for a single-cable pneumatic drive,
connect a pressure gage (with a scale in-
terval of 0.10 to 0.02 MPa and a scale of
1.6 MPa min.) to the coupling head with a
black cover, for a two-cable pneumatic
drive — to the coupling head with a red
cover;
- remove the cap (1) (Figure 5.8.1);
- using a wrench, screw in the cover (2)
into the body up to stop;
- turn on the compressor;
- start the engine and fill the cylinder
with compressed until the safety valve (6)
operates at a pressure of 0.85 to 1 MPa. If
the valve operates at a pressure of less
than 0.85 MPa or more than 1 MPa, adjust
it using the screw (8), first loosening and
then tightening up the nut (7).
Adjust the pneumatic system pressure
regulator as follows:
- gradually unscrewing the cover (2)
(Figure 5.8.1), adjust the force of the
springs (3, 4) so that the air pressure in
the cylinder, which makes the discharge
valve (5) open, be 0.77 to 0.8 MPa
- mark this provision of the cover (2)
applying paint to the threaded part of the
housing and put on the cap (1);
- in the cylinder, crack open the con-
densate drain valve and decrease the air
pressure to 0.65 to 0.7 MPa. At these val-
ues, the pressure valve (5) must close and
switch the compressor to filling the cylind-
er with compressed air;
- disconnect the test pressure gage
from the coupling head.
1 — cap; 2 — cover; 3, 4 - spring; 5 — pressure
relief valve; 6 — safety valve; 7 — locknut; 8 —
screw
Fig. 5.8.1 — Checking and adjusting pneumatic
system pressure regulator