MTZ 921 User Manual

MTZ

821/821.2/821.3

921/921.2/921.3/921.4

OPERATION

MANUAL

921 – 0000010 RE

CONTENTS

Section 1. Introduction. International marks ........................................................................................ 4

Section 2. Safety regulations ................................................................................................................ 6

Section 3. Technical specifications .................................................................................................... 19

Section 4. General information. Tractor layout and operation .......................................................... 23

Section 5. Controls and instruments .................................................................................................. 25

Section 6. Preparation to work and work order ................................................................................. 38

Section 7. Operation and adjustment regulations ............................................................................... 48

Section 8. Rigging .............................................................................................................................. 60

Section 9. Troubleshooting ................................................................................................................ 71

Section 10. Maintenance .................................................................................................................... 75

Section 11. Storage .......................................................................................................................... 100

Section 12. Transport ....................................................................................................................... 100

Section 13. Appendix ....................................................................................................................... 101

2

IMPORTANT!

In case of tractor bein g used by a customer or is lent or leased prior to starting operating it ensure
the operator:

A. . Is aware of safety measures and correct use.
B. . Has read and understood contents of the present operation manual.

NOTICE!

Due to constant product improvement structure of certain assembly units and parts may contain
alterations not mentioned in the present edition.
Some technical d ata and figures i n the p resent d ocument s ma y differ from actual for your machine.
Dimensions and weights are approximate (for reference only). Contact MTZ dealer for details.
General note: “Left” and “Right” terms in the present document are referenced from point of view
of a viewer behind the tractor moving forward.

TO OPERATOR’S ATTENTION!

1. Carefully read the present manual prior to running the tractor and strictly observe its
regulations.

2. Use seasonal diesel fuel according to the manual. Reduce engine oil change interval twice
when using fuel with up to 1% sulphur content.

3. Never allow idle engine operation exceed 15 minutes.

4. Keep in mind that diesel engine may be started with gear lever in most left position only (in
drive range engagement positions I or II).

5. With the tractor operating without rear PTO free two-speed PTO drive sw itch should be set to
position I (540rpm), free synchronous PTO drive lever should be set to neutral (middle) position,
control lever should be set to “PTO off” position (see “Controls and instruments” section).

6. Synchronous drive of rear PTO should not be used with track unit movin g faster than 8 km/h.
Otherwise tractor powertrain may be badly damaged.

7. Operation at 9th gear is allowed in overdrive only (range II).

8. Tractor cab is equipped with a single seat and only operator is allowed to stay into.

9. Certain tractor components are placed into SPS case, toolbox or cab at dispatch from the
factory. These should be installed by the user himself.

10. When commissioning new batteries remove sealing film from vents or cut afflux out of
polyethylene plugs.

11. Do not allow tractor operation with friction clutch engaged or not completely disengaged.

12. To start moving ensure hand parking reserve brake disengaged.

13. Set FDA switch knob to “driven” position in order to operate the tractor with no cardan shafts.

14. Never operate tractor in closed compartments with insufficient ventilation (air exchange):
exhaust gases may be fatal.

15. Never tow tractor with front wheel lifted up, otherwise FDA drive may fail leading to
emergency conditions.

16. Never lift machine front up with a towing shackle. Use the shackle to tow the tractor only.

17. Never perform maintenance or other works in fan or drive belt area with running engine.

18. Manufacturer never stops improving the machine, thus machine structure or operation rules
may be subject to alterations not reflected in the present manual.

3

Section 1. INTRODUCTION. INTERNATIONAL MARKS

The present manual contains basic technical data, description of structure features, controls,
operation and maintenance for the following tractor models:
MTZ-821 (D243; 4x4), MTZ-821.2 (D243.S; 4x4),
MTZ-821.3 (D245.43S2; 4x4)
MTZ-921 (D245.5; 4x4), MTZ-921.2 (D245.5S; 4x4),
MTZ-921.3 (D245.5S2; 4x4).
MTZ-921.4 (D245.5S3A; 4x4)

4x4 tractors MTZ 821/821.2/921/921.2/921.3/921.4 is a garden-and-vineyard version of
universal wheeled tractor-cultivator MTZ-822/922 featuring smaller dimensions and ground
clearance. These tractors are aimed at performing different works at fruit plantations, in gardens and
vineyards, as well as in industry, construction, public services and transport, equipped with rigs,
semihinged machines, towing machine and appliances.

Used abbreviations and acronyms

AB - accumulator battery
DL - differential lockup
QC - quick coupler
PFE - paper filter element
UBGP - upper bevel gear and pinion of front driving axle reduction gears
UDP - upper dead point of engine piston
PTO - power take-off
PIC - power input connection
HMS - hydraulic mounted system
HPS - hydrostatic power steering
SM - shift maintenance
SPS - spare parts set
RH - rear hookup
CFE - control filter element for diesel engine air filter
MFE - main filter element
GB - gearbox
TMA - tractor machine assembly
FC - friction clutch
H - hookup
FDA - front driving axle
TM - technical maintenance
TC - towing coupler

4

International symbols

In relation to instruments and controls use manufacturer uses standard international symbols.
Symbols and their descriptions are given below.

− See manual

− Brake

− Hand brake

− Horn

− Alarm signaling

− Fuel

−

Coolant

− Electric starting preheater

− Engine speed

− Engine oil pressure

− Engine coolant temperature

− Controls operation

− Fast

− Slow

− Forward

− Backward

− Battery charging

−

Cab limp

− Side lights

− Turn indicators

− Upper beam

− Lower beam

− Open

− Close

− Gradual change

− RH lever down

− RH lever up

− External cylinder, push-out

− External cylinder, retraction

− External cylinder, floating

− Clogging air filter

−

− Operation lights

− Differential lockup

− Power take-off engaged

− Front axle engaged

− Fan

− Screen washer

− Windshield wiper

− Rear window washer and wiper

− Trailer turn indicator

− Engine start (starter control unit

indicating lamp)

5

ATTENTION! Do not start engine from
outside operator’s place. Always stay in the

and operating controls.

Section 2. SAFETY REGULATIONS

Carefully follow precautions and regulations
in tractor operation and maintenance to ensure
work safety.

General notes

1. Carefully study the present operator’s

manual prior to operating the tractor.
Insufficient knowledge on driving and
operating the tractor may cause accidents.

2. Specially trained and qualified operators are

allowed to use the tractor, only.

3. Use tractor’s safety belt, if any, in

operation. Contact dealer otherwise.

4. Never take passengers i nto the tract or’s cab

as there is no seat provided.

5. Keep all warning labels clean. Replace

damaged or missing labels.

6. Thoroughly inspect the tractor, trailed

machinery, rigs and coupling prior to
commencing work. Ensure its complete
operability prior to commencing work.
Trailed agricultural machines and
transporting trailers should be equipped
with rigid hitches to prevent them swaying
and tractor being run down while
transporting, and with safety chains and
cables.

7. Prior to starting the engine engage parking

brake, free PTO switch should be turned
OFF, PTO gear changing rod
(“Synchronous/Free”) should be set neutral,
range and gear chan ging lever sh ould be set
neutral.

Safety regulations for tractor operation

cab at operator’s seat when starting the engine

8. Never start engine with towing to avoid

intensive engine parts wear.

9. Never start engine and never operate

controls from outside operator’s place.

10. Warn surrounding and working on trailed

machinery persons prior to commencing
work.

11. Never leave tractor in motion.

12. Turn PTO off, stop the engine, set PTO

switching rod neutral, engage parking brake
and pull starter key out.

13. Do not operate the tractor in enclosed

compartments with insufficient ventilation
– exhaust gases may lead to death!

14. In case of engine or steering fail during

operation immediately stop the machine.
Steering with stopped engine required much
greater force applied.
Non-operating engine with no pressure in
steering system lights oil pressure indicator.

15. Do not stay under lifted agricultural

machines. Never leave rigs lifted up for
long stops.

16. Be careful not to exceed maximum total

weight of tractor and coupled machinery
and axles loads as pe r S e ct io n 3: “Tech ni c al
specifications”.

17. Be careful not to injure a person or

damage property while lifting agricultural
digs up and down and turning the tractor.

18. Cardan shaft transferring torque from

PTO to machinery tips should be enclosed.

19. Ensure any supplementary equipment and

auxiliaries are installed correctly and fit
your tractor.
Keep in mind danger of misusing a tractor
for yourself and other persons.
Do not use equipment not designed to be
installed onto a tractor.

20. Be careful not to roll over. Choose safe

speed according to road condition,
especially when driving off-road, crossing
trenches and slopes and in sharp turns.

21. Widen tractor’s wheel track as much as

possible for driving at slopes.

22. Avoid sharp turns with full load and at

high speed.

23. To use the tractor for transporting:

• Widen wheel track as much as possible;

• Interconnect brake pedals, adjust

simultaneous braking, if necessary;

• Check parking brake operability;

• Check light and sound signaling devices;

• Transporting trailers should be equipped

with rigid hitches and safety chains or
ropes;

6

• Never drive down the hill with gear

disengaged (coasting)!

Drive the same gear up and down the hill.

• Never drive down the hill with engine

stopped. Oil pump should operate for safe
steering;

• Never use trailers weighing more than a

half of tractor’s actual weight without
independent braking system. The faster you
are driving and the greater is towed weight,
the longer should be safe distance;

• Disengage FDA to avoid excessive drive

parts and front tires wear;

• Do not lock rear axle differential when

turning or driving faster than 10 km/h;

• Never stop at slope. In need to stop engage

the 1st gear and parking brake.

24. Stop the engine and ensure PTO end stop

prior to leaving the cab and disconnecting
machinery when working with PTO-driven
attachments.

25. Never wear loose cloths when operating

PTO or near rotating machines.

26. Always engage parking brake and block

rear wheels with wedges on both sides.
Ensure secure fixation of the machine.

27. Use synchronous PTO dr ive for lower GB

gears at speed not exceeding 8 km/h,
otherwise tractor’s powertrain may be badly
damaged.
Set independent and synchronous drives rod
to middle (OFF) position and replace PTO
end cap.

28. Never clean, adj ust or service PTO-driven

machines with running engine.

29. Driving with installed agricultural rigs

faster than 15 km/h is not allowed.

Safety regulations for maintenance

30. Never fuel the tractor up with running

engine.

31. Never smoke when fuelling the tractor up.

32. Do not fill fuel tanks to the full – leave

enough space for fuel to expand.

33. Never add gasol ine or mix es to diesel fuel

to avoid increased fire or explosion hazard.

34. Timely apply summer and winter fuels.

Fill fuel tank in the end of each day to
reduce condensation at night.

35. All operations related to engine or tractor

cleaning, preparation to work, servicing,
etc. should be done with stopped engine
and braked tractor.

36. Engine cooling system is constantly

pressurized with a valve in radiator’s filler
cap. Do not remove the cap with hot
engine. Always slowly turn the cap to
depressurize.

37. Be careful not to burn yourself when

discharging coolant or water from cooling
system, hot oil from engine, hydraulics or
transmission.

38. Be careful when servicing batteries –

spoiled electrolyte shall burn skin.

39. Avoid open fire close to the engine fuel

system and batteries to prevent explosion
hazard.

40. Keep tractor and its systems, particularly

brakes and steering, operable to ensure
personal safety for operator and
surrounding people.

41. Modifications to the tractor or its certain

components without prior approval by a
dealer and manufacturer are prohibited.

42. Remove filter mesh from fuel tank filler

neck to avoid fuel spillover when fueling
the machine up mechanically.
The filter mesh is provided for manual
fueling the tractor up in the field only.

43. Charge the tractor with oils and grease

recommended by the manufacturer only.
Application of other lubricants IS

STRICTLY PROHIBITED!

Safety regulations for electrics operation
and maintenance

44. Adhere the following safety regulations to

prevent damage to semiconductor devices
and resistors:

• Never disconnect battery terminals with

running engine – that would cause voltage
crest in charging circuit and damage to
electric devices.

• Never disconnect electric wires prior to

stopping the engine and turning all electric
switches off.

• Observe polarity when connecting wires

to the battery. Incorrect connection shall
lead to short-circuit and dama ge to electric
systems.

7

• Do not connect AB to electric system until

IMPORTANT! Do not turn starter and
instrument switch prior to full engine stop.

terminals and voltage polarity is verified.

• Never check for current with “a spark”

method that causes damage to electrical
equipment and fuses and wiring burn-out.

• Do not operate the tractor without battery

installed in electric system.

Fire safety regulations

45. The tractor should be equipped with fire-

fighting equipment, particularl y with spade
and fire-extinguisher. Operating tractor
with no fire-fighting means is not allowed.

46. Areas for storing tractors and fuels and

lubricants should be rounded with not less
than 3 m wide ploughed strip and provided
with fire-fighting means.

47. Charge tractors with fuels and lubricants

mechanically with engine stopped. Use
light at nights. Try to avoid fueling tanks up
from buckets.

48. Clean parts and assembly units from plant

residues prior to perform repair with
electro-gas welding in the field.

49. Prevent manifold and exhaust pipe

clogging with dust, fuel, straw, etc.

50. Prevent straw winding round rotating

parts of machinery coupled to the tractor.

51. Take appropriate fire-safety measures

when rinsing parts and assemblies with
kerosene or gasoline to avoid vapors
ignition.

52. Never operat e the tra ctor in fire-hazardous

areas with removed bonnet and other
protective devices from hot engine parts.

53. Never use open fire to warm up oil in the

engine oil pan, when filling tanks with fuel,
or to burn radiator core contaminants out.

54. Emerging fire seats should be buries under

sand, covered with tarpaulin, bagging or
other compact material.

55. Avoid inflammable materials being close

to exhaust manifold and pipe with running
engine.

56. Apply silencer or separate spark

preventers in exhaust system when
harvesting hay or straw or working in areas
of high fire hazard.

8

Parameters

Value

265/70R16 (f)
420/70R24 (r)

12,4L16 (f)
14,9R30 (r)

A

Length with loads and rig attachment, mm

4280

Length without loads with rig attachment in transporting
position, mm

A”

Length at overall wheels diameters, mm

3450

Width with front and rear rig attachment in transporting
position, mm

B

Width, mm

1550

C

Height, mm

2350

D

Wheel base, mm

2440

E

Front axle track, mm

1220-1420

F

Rear axle track, mm

1160-1585

Ground clearance under the rear axle, mm

257

Ground clearance under the front axle, mm

325

Delivery weight, kg

4000±100

Section 3. TECHNICAL SPECIFICATIONS

Overall dimensions and weight

Front and rear tires

A’

4225

4500

9

Tractor component numbers

Tractor’s nameplate with stated machine and engine
serial numbers (outside the right cab side).

Serial number of the tractor is repeated on the left rail
of the half-frame or at front loads plate.

Engine number (repeated at the en gine nameplat e fix ed
to the engine head).*

Gearbox number (at the left side of gearbox casing).

*

D-243.S for MTZ-821.2; D-245.43S2 for MTZ-821.3; D-245.5 FOR MTZ-921; D-245.5S for MTZ-921.2, D-245.5S2

for MTZ-921.3., D245.5S3A for MTZ-921.4

10

Friction clutch number (on the left side of clutch
casing).

Front driving axle number (on the left front side of
FDA casing).

Transmission number (to the right from rear view at
connection to gearbox).

11

Diesel engine

D-243.S

D-245.43S2

D-245.5

D-245.5S

D-

921.3)

D-

921.4)

4-tact, in-line,

4 tact,

intercooler

4 tact,

er

4-tact, in-line, turbocharger,

Number of

pcs.

Carburetion
mode

Compression

(estimated)

Cylinder
diameter, mm

Piston stroke,
mm

Displacement
, l

Operation
sequence

Cooling
system

Rated speed,
rpm

Max. speed,
rpm

Min. speed,
RPM

Rated power,
kW

Max. torque,
Nm

411 (at 1400

RPM)

Lash between

rocker at cold
engine, mm

Fuel injection

UDP, deg.

Fuel injection

MPa

Model

Type

cylinders,

ratio

D-243

(MTZ-

821)

(MTZ-

821.2)

naturally aspirated

16±1 17±1 15±1 17±1

(MTZ-821.3)

in-line,
turbocharger,

Direct fuel injection

(MTZ-

921)

in-line,
turbocharg

4

110
125

4.75

(MTZ-

921.2)

intercooler

245.5S2
(MTZ-

245.5S3AM
(MTZ-

inlet (outlet)
valve and

lead angle to

2200 1800
2380 2070 1980 2070

600 800 700 800

60 62 65 70

298 (at 1400 RPM)

0.20-0.35

(0.20-0.35)

19-21 15-17 3-5

1-3-4-2

Water-cooled

397 (at 1000 RPM) 464 (at 1400 RPM)

0.15-0.30

(0.35-0.50)

(8-10)*

(7-9)**

3-5

pressure,

*

With fuel injection pump “Motorpal”

**

With fuel injection pump “Yazda”

21.6-22.4 23.5-24.7 21.6-22.4 23.5-24.7

12

Diesel engine feed system
Fuel pump: 4-plunger, in-line, with boost

pump.

Regulator: mechanical all-mode.
Fuel filters: coarse filter and fine filter (with

replaceable paper filter element).
Turbocharger*: centripetal radial turbine on a
single shaft with centrifugal compressor. Type:
C14-126-01 (Czech Republic).
Fuel type: diesel:
Basic:

• L-0.2-40, L-0.2-62 (summer)

• Z-0.2 -35°C, Z 0.2 -45°C (winter)

• A-0.2 (up to -45°C)

Substitutes:

• L-0.5-40, L-0.5-62 (summer)

• Z-0.5 -35°C, Z 0.5 -45°C (winter)

• A-0.4 (up to -45°C)

Foreign:

• BS-2869, ASTM-D-VV-F-800 and other

(summer)

• DEF 2402B, SAE and other (winter)

• SAE VV-F-800 (up to -45°C)

Fuel tank capacity: 95 l.
Air filter: “Donaldson” with dry paper filter

element.

Engine lubrication system
Type: combined, with oil cooler (with water-

oil heat exchanger)**.
Oil filtering: prefilter mesh and fine
centrifugal filter (paper filter element)**.
Min. oil pressure: 0.08 MPa (0.8 kgf/cm2) at
600 RPM.
Normal oil pressu re: 0.25-0.35 MPa (2.5-3.5
kgf/cm2) at 1800 RPM.
Max. pressure at co ld engin e: up to 0.6 MPa
(6 kgf/cm2).

Refill capacity: 12 l.
Motor oil brands:

Basic:
+5°C to +50°C:

• M-10DM;

-40°C to +5°C:

• M-8DM;
Substitutes:

*

Not for MTZ-821.

**

For MTZ-821.3/921.3.

+5°C to +50°C:

• M-10G2k;

-40°C to +5°C:

• M-8G2k;
Foreign:
+5°C to +50°C:

• Shell, Rotella, TX 30, HESSOL and other;

-40°C to +5°C:

• Shell, Rotella, ТХ 20W/20, HESSOL and

other;

Friction clutch
Type: friction, dry, single-disk, with

tangentially suspended pressure plate. Plate
diameter – 340 mm.

Drive: hydrostatic with suspended pedal.

Engine cooling system
Type: water-cooled, closed, with forc ed water

circulation, with temperature control by
thermostat.
Normal operating temperature: 75°C to
95°C.

Thermostat: TS-107.
Cooling system capacity: 17 l (19 l) **.
Coolants:

Basic:

• OJ-40, OJ-65.
Substitute:

• Tosol A40M, Tocol A65M.
Foreign:

• MIL-E-5559, FL-3 Sort, S-735.

Steering
Type: hydraulic displacement with hydraulic

cylinder in steering trapezium.

Pump performance:

31 l/min for MTZ-821/821.2;
25 l/min for MTZ-

821.3/921/921.2/921.3/921.4.
Hydraulic cylinder: double-acting, cylinder
diameter 50 mm, piston stroke 250 mm.

13

Metering pump: volumetric constant 160
cm3/turn, operating pressure up to 14 MPa.
Installed at front cab side.
Steering column: stepless height adjustment
within 100 mm.
Inclination adjustment: 25° to 40° with 5°
pitch. Steering wheel free move up to 25°.

Gearbox
Type: 18x4, mechanical, fixed-ratio, dual-

ranged, sliding gear transmission. 14x4
synchronized at request.

Multiplier

*

Type of both assemblies: mechanical with

direct and 1.36 step-up gears at multiplier and
direct and 1.32 step-down gears at back gear.
Form 18 forward-driving and 4 rearward­driving gears.

*

Back gear for MTZ-821/821.2.

14

Estimated tractor speeds in km/h at rated diesel engine cranksh aft speed 1800 RPM (GB – 9/2 +
multiplier; rear tires 14.9R30). MTZ-821.3/921/921.2/921.3/921.4.

15

Estimated tractor s peeds in km/h at rated diesel engine crank shaft speed 1800 RPM (GB – 9/2 +
multiplier; rear tires 420/70R24). MTZ-821.3/921/921.2/921.3/921.4.

16

Estimated tractor s peeds in km/h at rated diesel engine crank shaft speed 2200 RPM (GB – 9/2 +
back gear; rear tires 14.9R30). MTZ-821/821.2.

17

Estimated tractor speeds in km/h at rated diesel engine crankshaft speed 2200 RPM (GB – 9/2 +
back gear; rear tires 420/70R24). MTZ-821/821.2.

18

IMPORTANT!

e. Contact

workshops with specially trained personnel to dismount and repair tires.

Permissible load

change, ±%

Drive axle

8*

+40

20

+20

25

+7

30 0 35

-10

IMPORTANT! Use appropriate front and rear tires. Correctly chosen front and rear tires ensure

kinematic discrepancy and excessive tire wear.

Front tires

265/70R16

12.4L16

14.9R30

-

+

420/70R24

+

-

Tire

Load on tire, N (kgf) at internal pressure kPa (kgf/cm2) at 30 km/h

80

(0.8)

100

(1.0)

120

(1.2)

140

(1.4)

160

(1.6)

180

(1.8)

200

(2.0)

4900

(500)

5586

(570)

6272

(640)

6958

(710)

7644

(780)

8330

(850)

9015

(920)

5684

(580)

6566

(670)

7252

(740)

7939

(810)

8673

(885)

9359

(955)

9996

(1020)

14700

(1500)

15729

(1605)

17297

(1765)

18865

(1925)

19943

(2035)

13328

(1360)

14798

(1510)

16317

(1665)

17689

(1805)

19110

(1950)

1. Never exceed tire pressure recommended by the manufacturer.

2. Do not perform welding or other repair works on a disk with pressurized tir

Table of permissible tire load changes relative to tractor speed:

Max. permissible

speed, km/h

maximal performance, elongate tires service life and reduce powertrain components wear.
Combination of worn and new tires or tires with different diameters or rolling radiuses may result in

Tire combinations:

Rear tires

Permissible loads on tractor tires in relation to tire pressure:

265/70R16

12.4L-16

420/70R24

14.9-30 -

- -

-

To get optimal operational parameters set tire pressure within ranges from minimal to maximal in
relation to actual loads acting on tires and speed according to tables.
For machines requiring dig tractive effort set pressure as for 30 km/h.

*

Increase tire pressure by 25%.

19

Ambient temperature

Calcium chloride proportion, g/l of water

Up to -15°C

200

Up to -25°C

300

Up to -35°C

435

Tire

Quantity of liquid to put in, l

14.9-30

190

420/70R24

170

ATTENTION: Preparing a mix for ballast liquid always add calcium chloride to water and keep
stirring until it is completely dissolved. Use goggles when preparing a mix. In case of the mix

the eyes with cold clean water within 5 minutes and call for medical care as

soon as possible.

Ballast liquid

Additional wheel loading by filling wheel tubes with liquid is applied in case of insufficient wheel
traction to the ground in adverse conditions (overwet soils, etc.).

Note: it is preferably not to ballast from wheels as it affects tractor steerability.
In cold weather we reco mmend using calcium chloride and water mix according to the following
table:

Application of such a mix ensures low freezing point, increased solution density and safe and
efficient ballast. A tire should be filled with liquid up to 75% of its volume. While filling up with
liquid the tire valve should take the highest position.

The following table provides quantities of liquid to put in:

contact to eyes rinse

20

Rear axle
Main gear: pair of bevel circle-arc toothed

gears.

Final drives: pair of straight gears.
Differential locking mechanism: mechanical

with manual control (for operator’s left hand).

Brakes
Main brakes: rear wheels, twin-disc, dry,

hydrostatically-driven, with suspended pedal.
Parking brake: combined with main brakes,
with independent mechanical actuator.

Front driving axle
Type: portal.

Main gear: bevel circle-arc toothed gears.

Differential
Type: self-locking, limited-slip.

Final drives: two-support reduction gears

with bevel gearing.
Recommended transmission oils:
Basic:

• Tap-15V
Substitute:

• TSp-15K, TSp-10, TAD-17I
Foreign:

• HESSOL, BECHEM, HYPOID
Drive: from transfer box by two cardan shafts
with intermediate support.

FDA control: mechanical.
Operation modes:

• FDA off;

• FDA on forcedly;

• FDA on/off automatically.

PTO drive
Type: independent two-speed synchronous.

Master clutch: planetary reduction gear with

band brake.

PTO control: mechanical.
PTO end rotation speed:

Independent drive:

I – 540 RPM for PTO at 1631 (2081)* RPM
for engine;
II – 1000 RP M for PTO at 1673 (2184)** RPM
for engine.
Synchronous drive:

• 3,90 rotations per path meter with

synchronous drive (tires 14.9R30);

• 4,45 rotations per path meter with

synchronous drive (tires 420/70R24).

PTO end: 6- or 8-splined (540 RPM) and with
21 splines (1000 RPM).

Rotation direction: clockwise.

Hydraulic mounted system (HMS)
Type: remote-cylinder system with hydraulic

jack featuring two actuating hydraulic
cylinders built in the rear hitch. HMS ensures
height, power and combined control.
Hydraulic system outputs; two side and two
rear outputs (rear side output is linked to the
rear right output).

Oil pump
Type: gear pump delivery discharge rate not

less than 45 l/min at engine speed of 1800
RPM.

Hydraulic distributor: RP 70.
Type: running-through, three-sectional, four-

position.
Actuating cylinder: two plunger hydraulic
cylinders Ø80 mm, plunger stroke 220 mm.

Recommended oils for HMS:

• Motor oils: M-10G2 updated, M-8G2k, M-

10G2k;

• Industrial oil: BECHEM Staroil No.32,

HUNOLD Hydraulikoel HLP 32.

Hydraulic system oil tank capacity: 45 l.

*

For MTZ-821/821.2

21

Pneumatic system

Compressor

Type: single-cylinder, piston-type, air-cooled.
Dimensions: 72x38 mm (diameter – 72 mm,
stroke – 38 mm).

Trailer brakes control
Type: pneumatic, single- or double-line,

blocked with tractor brakes.
Pressure: 6.5-8.0 kgf/cm2 (0.65-0.8 MPa).
Pressure limited with safety valve: 8.5-10.0
kgf/cm2 (0.85-1.0 MPa).

Rear rigging mechanism
Type: jointed four-section of Cat.2.

Load capacity: 25 kN (at 610 mm from

suspension axle.
Suspension axle adjustment from 680 mm to
870 mm at request.

Electric equipment
Vehicle network voltage: 12V.

Starting system voltage: 12V.
Battery: 12V, 2x90 A∙h (located on the upper

half-frame rail).

Feeding system: on e 12V battery. 12V starter
feeding.

Generator: 12V, 1000W.
Starting aids*: glow plugs.

Lighting and warning light system

• Front embedded road headlamps with

upper and lower beams;

• Front and rear operation lights;

• Front and rear lights;

• Alarm lights;

• Tractor-and-trailer lights;

• Beacon light.

Tires

Front: 12.4L16; 265/70R16.
Rear: 14.9R30; 420/70R24.

*

For MTZ-821.3/921.3.

22

Section 4. GENERAL INFORMATION. TRACTOR LAYOUT AND OPERATION

Garden-and-vineyard tractors MTZ-821,
MTZ-821.2, MTZ-821.3, MTZ-921, MTZ-

921.2, MTZ-921.3 and MTZ-921.4 are
versions of universal cultivating tractor MTZ­922 and have the following distinctive
features:

• Independent fuel tank for 95 l loc ated near

the left cab footboard;

• Gearbox – mechanical, with two operation

modes (synchronized 14x4 at request);

• Hydraulic system oil pump actuator

located to the right from clutch casing;

• Rear ax le dif ferential lock – is mechani cal

with two operation modes:

1. Lock

2. Forced lock

Locking clutch is splined.

• Front driving axle featured with two-

support bevel reducing gears;

• Rear PTO is mechanically controlled.
Tractor frame consists of half-frame, friction
clutch casings, gearbox and rear axle.
Diesel engine is rigidly fixed to the friction
clutch casing through the rear plate and is
mounted onto the front rail with hinged
bearing.
Following powertrain components are located
behind the engine:

• Single-disk friction clutch;

• Mechanical 9/2 gearbox with gear-change

lever to the right. Mechanical multiplier*
(step-up gear) is locat ed bet ween clu tch and
gearbox to double numbers of forward and
rearward gears. The multiplier is controlled
with a lever at the left operator’s hand;

• Rear PTO with 2-speed independent and

synchronous drives. PTO is engaged and
disengaged with a lever at the right
operator’s hand;

• Front driving axle (FDA) with two-

support bevel reduction gears has increased
load-carrying capacity due to bevel roller
bearings into the reduction gear pivot
supports.
FDA drive consists of a transfer box,
intermediate and front cardan shafts and
intermediate bearing with multidisc wet

friction clutch. FDA is driven by the
secondary gearbox shaft to ensure
synchronic rotation of the front and rear
wheels at every gear. FDA is mechanicall y
controlled by a lever with three fixed
positions: “FDA on”, “FDA on/off
automatically” and “FDA on forcedly”.
FDA is conn ected to a beam by two hollow
axles allowing the axle with wheels to
swing transversely.

• Parking brake includes main brakes with

independent mechanical control.

Hydraulic rigging system consists of a
hydraulic jack with two vertical cylinders and
embedded regulator, of a rigging mechanism
and a distributor to control external consumers
(external cylinders).
Hydraulic jack performs the following
functions:

• Tractor suspension lifting up and down

with its dead weight;

• Automatic lifting suspension down to the

set position relative to the tractor
(positioning adjustment);

• Adjusting ploughing depth according to

soil resistance (force adjustment);

• Ploughing depth force adjustment with

positionally limited maximal depth
(combined adjustment);

• Automatic pump discharge in transport

condition.
The hydraulic jack is controlled with two
handles of force and positioning adjustment,
accordingly.
Force adjustment handle is the closest to the
seat at the side board. Its movement range
corresponds to full ploughing depth range
from minimal to maximal.
Positioning handle is located to the right from
force adjustment handle. Its movement range
corresponds to suspension positions from the
lowest to the transport.
Distributor is of flowing through type without
bypass valve. Is consists of 3 sections, each
having four positions: “neutral”, “lifting up”,
“lifting down”, and “floating”.
The tractor is equipped with pneumatic system
to control braking systems of trailers in single-

*

Back reduction gear (back gear) for MTZ-821/821.2.

driven mode.

23

Towing coupler: double crossbeam (ТСУ-
1Ж-01) is united with rear digging mechanism

into a single assembly unit. At request a single
crossbeam may be mounted meeting DIN
requirements and fixed on the lower rod jaws.
Tractor cab is safe and comfortable.
The cab is equipped with venting and heating
system with air intake through filters over the
side windows. Design of filters in venting
system allows its partial self-cleaning in
motion.
Naturally the cab is vented through a hatch in
the roof and opening rear and side windows.
The cab is equipped with a comfortable seat
with mechanic suspension and hydraulic
damper (the seat is adjusted per operator’s
height and weight). Steering wheel is located
right in front of the seat and may be thrown
over to ease getting into and out of the cab.
The steering wheel is height-adjusted by 100
mm.
Control station is designed to ensure comfort
working conditions for operator and as
convenient tractor control as possible.
Instrumental board with fundamentally new
electric dashboards and electronic tacho­speedometer are located on the steering
column, cable-driven fuel supply control
handle is located at the right wing of the
dashboard, gearbox control arm is located to
the right, hydraulic jack control arms are
situated at the right control board, parking
brake control lever is located to the left, rear
PTO control arm is situated at operator’s right
hand, multiplier control arm is located to the
left from the dashboard, distributor control
arms are located to the right from operator’s
seat. A board with (from the left to the right)
heater, front and rear working lights, rear
window washer and wiper switching keys.
Electric circuit fuses block is situated near the
board under a cover. Rear-view mirrors are
located on both sides of the cab. Additional
working lights are mounted on the roof.
Tractor design allows installation of additional
process equipment (available at request) and
extra loads.

24

Section 5. CONTROLS AND INSTRUMENTS

1. Switch for working lights at front brackets

2. Starter and instruments switch

3. Turn indicators, upper and lower beam and horn switch

4. Multiplier (step-up gear) switching handle

5. Engine stop knob

6. Remote ground switch

7. St eeri ng wheel

8. Front screen washer and wiper switch

9. Fuel supply control arm

10. Alarm lights switch

11. Central light switch

25

12. Voltage indicator

13. Engine coolant temperature indicator

14. Pneumatic system pressure indicator

15. Fuel tank level indicator

16. Engine oil pressure indicator

17. Control lights block

18. Tacho-speedometer

19. Radio or audio receiver (if any)

20. Recirculating flaps

21. Heater, front and rear working lights, rear screen washer and wiper keys board

22. Sun visor

23. Air deflector

24. Clutch pedal

25. Steering wheel inclination control rod

26. Brake pedals

27. Fuel supply control pedal

28. Heater, front and rear working lights, rear screen washer and wiper circuit fuse block cover

29. Cab lamp

26

Fuel supply is controlled with a handle (9) or

IMPORTANT! To control with a pedal (27)

set the handle (9) to the middle position.

IMPORTANT! For synchronized multiplier*
(1) ON and OFF positions are reversed.

NOTE!

stable engine speed with pressed clutch

(1) lever has no fixed

position is allowed in winter to aid engine
start only.

INPORTANT! Activate the pump at low idle

cold engine start or for maintenance.

pedal (27) (see fig. at page 5-1). Moving the
handle up (push) increase fuel supply and
engine speed, and vice versa.

Multiplier* is contro lled with a lever (1) with
two fixed positions:

• ON – most rear position (pull).

• OFF – most forward position (push)

(direct drive).

1. The multiplier* (1) is switched at minimal

pedal.

2. The multiplier*

neutral position. Setting it to the middle

Rear axle differenti al lock is controlled with
a handle at the left operator’s hand.
Move the handle fully up to lock the
differential. The differential is locked
automatically after the handle is released.

Gearbox is controlled with a lever (N) as
follows:

• Chose required range (I or II) by turning

the lever from neutral to the most left (pull)
and pushing it forward or pulling back to
engage required range. Return the lever to
neutral position;

• Select required gear according to

switching layout and engage.

*

Back gear for MTZ-821/821.2.

run of the engine only. Turn the pump off for

Rear PTO control

Independent and synchronous drives switching
handle.

The handle (2) has three positions:

• “Independent drive ON” – utmost up

position;

• “Drive OFF” – middle position;

• “Synchronous drive ON” –lowest

position.
Engage independent and synchronous drives at
lowest stable engine speed.
To engage synchronous drive:

• Start the engine;

• Fully press clutch pedal and engage 1st

gear;

27

• Slowly release the clutch pedal and

INPORTANT! Synchronous PTO drive shall

km/h only. Otherwise the tractor’s powertrain

Set the handle (2) to the middle position

not using PTO.

simultaneously move the handle to the
lowest position.

Two-speed independent PTO drive switch

Independent PTO drive lever (2) has two
positions:

• I – 540 RPM – fully clockwise (down

view);

• II – 1000 RPM – fully counterclockwise.
To set required PTO end rotation speed loosen
bolt (1), turn the lever (2) to I or II position
and tighten the bolt (1).

be use at lower gears at speed not ex ceeding 8

may be badly damaged.

“Drive OFF” and replace PTO end cap when

Parking brake control arm

• Upper position of lever (4) – parking

brake ON;

• Lower position of lever (4) – parking

brake OFF.
To disengage the parking brake press button
(3) of the control arm and press the lever fully
down.

Turning rear PTO on and off

Rear PTO is controlled with a lever (3) with
two positions:

• PTO ON – utmost rear position;

• PTO OFF – utmost forward position.

Compressor control

The handle (4) has two positions:

• Compressor ON – turn the knob by 180°

to orient an arrow at the knob against
tractor driving direction;

• Compressor OFF - turn the knob by 180°

to orient an arrow at the knob along tractor
driving direction.

28

ATTENTION! Switch the compressor with
engine stopped or low idling.

IMPORTANT! Set lever (1) to “FDA ON
forcedly” position to operate tractor without
cardan shafts.

NOTE! Handles (5, 6) allow combined

(5) and control by handle (6).

IMPORTANT! Hydraulic jack cannot be

(2, 3, 4) in Lifting Up or Lifting Down
position.

FDA drive control

PMV drive transfer box control arm (1) has
three fixed positions:

• FDA OFF – upper position. Used for

driving hard roads;

• FDA ON/OFF automatically – middle

position. FDA is automatically switched on

and off by freewheeling clutch depending

on rear wheels slippage. Used for various

field works;

• FDA ON forcedly – lower position. Used

briefly for performing works on loose or

wet soils and, if necessary, at backing.

• Most rearward – transporting position.

Hydraulic system distributor control

Each of three levers (2, 3, 4) controls external
cylinders and has four positions:

• Neutral – upper middle position (fixed);

• Lifting Up – upper non-fixed position.

Released handle returns to Neutral (lever
(4) has fixed Lifting Up position);

• Forced Lifting Down – lower middle non-

fixed position between Floating and Neutral
positions. Released handle automatically
returns to Neutral;

• Floating – lower fixed position.

RH jack control

Hydraulic jack is controlled with two arms (5,

6) at the right board for the right operator’s
hand.
Force adjustment handle is located closer to
the operator and has the following positions:

• Most forward – maximal tillage depth;

• Most rearward – minimal tillage depth.

Positioning adjustment (5) handle has the
following positions:

• Most forward – minimal tool height over

the ground surface;

adjustment with tilting depth limited by handle

controlled with arms (5, 6) with any of handles

29

Indicators and switches

Starter and indicators switch (1)

Has four positions:

• 0 – “OFF”;

• I – “Indicators and control lights block

ON”. Oil pressure alarm lights at engine oil

pressure indicator (16), page 5-1, and alarm

buzzer sounds;

• II – “Starter ON” (non-fixed position).

Control light and alarm buzzer go off after

engine is started;

• III – “Radio feeding”. Turn the key

counterclockwise.

Remote AB switch (2)

The switch is on with button (2) pressed.
Repeated pressing switched the battery off.

Central light switch (3)

Has three positions:

• I – OFF (right part of the key is recessed);

• II – Front and rear sidelights, license plate

lighting, dashboard instruments lighting and

additional lights at trailed machi ne are ON

(middle position);

• III – All consumers od position II and

road lights are ON (left part of the key is

recessed).

Understeering switch (left) (1)

Allows switching on turn indicators, switching
between upper/lower beam of headlamps,
upper beam signaling, horn activation.
Turn indicators are switched by moving the
arm forward/rearward.

Lower/upper beam of headlamps

To light headlamps on set the central light
switch (1) to position III (see above) and set
the switching arm to the middle position
“Lower Beam”. Upp er beam is activated with
pushing the switching arm to stop. Arm
positions for upper and lower beams are fixed.
To blink with upper beam pull the arm to stop
from Lower Beam position regardless the light
switch position.

Understeering switch (right) (2)

Allows switching-on windshield washer and
wiper at 1st (low) or 2nd (high) speed.

Windshield wiper switch has three fixed
positions:

30