AGCO Challenger MT255B User manual

© AGCO Corporation, 2006 All rights reserved.
Part Number 79024234 A Rev. (English)
Printed in U.S.A.
November 2006
Challenger®
MT255B
Standard Compact Tractor
SERVICE MANUAL
79024234 A Rev.
CONTENTS
INTRODUCTION.....................................................................................................................................................01
GENERAL INFORMATION ....................................................................................................................................02
DISASSEMBLY ......................................................................................................................................................03
ENGINE ............................................................................................................................................................... 04A
ENGINE ACCESSORIES .................................................................................................................................... 04B
CLUTCH .................................................................................................................................................................05
TRANSMISSION.....................................................................................................................................................06
REAR TRANSMISSION..........................................................................................................................................07
REAR AXLE HOUSING .........................................................................................................................................08
FRONT AXLE .........................................................................................................................................................09
HYDRAULIC...........................................................................................................................................................10
STEERING SYSTEM..............................................................................................................................................11
ELECTRICAL .........................................................................................................................................................12
LUBRICATION AND MAINTENANCE ...................................................................................................................13

79024234 A Rev. 01-i
Contents
Challenger®
MT255B
Standard Compact Tractor
SERVICE MANUAL
79024234 A Rev.
01 - Introduction
Contents
INTRODUCTION
General Information ....................................................................................................................................... 01-1
INDEX ............................................................................................................................................................... 01-3
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01-ii 79024234 A Rev.
Contents
NOTES
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79024234 A Rev. 01-1
Introduction
INTRODUCTION
GENERAL INFORMATION
This service manual has been prepared to provide the
information and suggestions necessary for servicing the
Tractor equipped with the mechanical transmission.
These include construction, specifications, removal and
reinstallation of the components, disassembly and
reassembly instructions, inspection and adjustment
instructions, troubleshooting, general precautions etc.
Figures mentioned in this manual are standard values
established by AGCO, Massey Ferguson and Challenger
for the Tractor, consequently when a non-AGCO / Massey
Ferguson / Challenger part has been installed on the
machine or adjustments and repairs have been made in a
manner other than as specified in this manual, the
pertinent values mentioned herein are no longer valid.
AGCO / Massey Ferguson / Challenger does not assume
responsibility for problems or damage caused by a value
deviation due to maladjustment or by the use of
unauthorized parts.
Servicing procedures outlined in the manual contain
sufficient information to return all component parts of a
machine to new condition. In discussion of each
component part, it is assumed that a complete overhaul is
being performed, consequently, complete disassembly
and reassembly are outlined. The machine is relied upon
to decide how far disassembly must be carried out when
complete overhaul is not required.
Study unfamiliar service procedures thoroughly and
understand them clearly before attempting disassembly.
Specific data essential for proper overhaul, such as
running clearances and torque values, have been
provided in interline of inspection and reassembling
procedures of each group section.
This manual was compiled from latest information
available at time of publication. However, AGCO / Massey
Ferguson / Challenger reserves the right to make
changes at any time without notice.
Whenever the terms “left” and “right” are used, this means
as viewed by the operator when seated in the operator’s
seat.
Whenever servicing the machines, pay sufficient attention
to the operational safety to protect you and other persons
around the machines from danger by following carefully
the instructions given in the manual. Never take chances!
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Introduction
01-2 79024234 A Rev.
NOTES
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79024234 A Rev. 01-3
Index
INDEX
G
General Information ............................................. 01-1
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Index
01-4 79024234 A Rev.
NOTES
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79024234 A Rev. 02-i
Contents
Challenger®
MT255B
Standard Compact Tractor
SERVICE MANUAL
79024234 A Rev.
02 - General Information
Contents
GENERAL INFORMATION
Tractor Type and Other Identification Markings ............................................................................................. 02-1
Tractor, Engine Model, and Respective Serial Numbers ............................................................................... 02-2
Specifications ................................................................................................................................................. 02-3
General Dimensions ...................................................................................................................................... 02-5
General Precautions for Separation and Reinstallation ................................................................................. 02-6
Before Operation ..................................................................................................................................... 02-6
Precautions To Be Followed When Installing Common Parts ................................................................. 02-6
Speed and Reduction Ratios ......................................................................................................................... 02-9
Tires ...................................................................................................................................................... 02-10
PTO Speeds & Reduction Ratio ............................................................................................................ 02-10
INDEX ............................................................................................................................................................. 02-13
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02-ii 79024234 A Rev.
Contents
NOTES
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79024234 A Rev. 02-1
General Information
GENERAL INFORMATION
TRACTOR TYPE AND OTHER
IDENTIFICATION MARKINGS
FIG. 1: Identification markings:
(1) Tractor serial number
(2) Chassis serial number
(3) Engine information
FIG. 1
i-9686b
1
3
2
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General Information
02-2 79024234 A Rev.
TRACTOR, ENGINE MODEL, AND
RESPECTIVE SERIAL NUMBERS
FIGS. 2–3–4: Each tractor is identified by means of the
tractor model and serial numbers. As a further
identification, the engine and chassis are also provided
with identification numbers. They are provided as shown.
FIG. 2
I6090
FIG. 3
FIG. 4
I6006
i-7051

79024234 A Rev. 02-3
General Information
SPECIFICATIONS
These specifications are subject to change without notice.
Engine
Make.....................................................................................................................................................................ISEKI Diesel
Model ............................................................................................................................................................ E3CF-VB27
Type.....................................................................................................................................Indirect injection, overhead valve
Displacement ................................................................................................................................... 1.463 lit. (89.3 cu in)
Number of cylinders............................................................................................................................................................... 3
Bore ................................................................................................................................................................ 86 mm (3.385”)
Stroke.............................................................................................................................................................. 84 mm (3.307”)
Engine horsepower (net) @ engine revolution min (rpm) ...................................................................................27.6 / 2500
PTO horsepower (estimate) .................................................................................................................24.2 @ 585 PTO rpm
Firing order.......................................................................................................................................................................1-3-2
Compression ratio.......................................................................................................................................................... 21.7:1
Low idle speed.................................................................................................................................................. 930 - 970 rpm
High idle speed ............................................................................................................................................ 2650 - 2750 rpm
Valve clearance (cold) - intake and exhaust ................................................................................................ 0.35 mm (.014”)
Air cleaner..................................................................................................................................... Single stage - dry element
Engine cooling .................................................................................................................................Liquid, forced circulation
Cold starting......................................................................................................................................................Glow plugs (3)
Transmission
Primary .......................................................................................................................................................................... F3/R1
Range..................................................................................................................................................................................... 3
Gear selections.............................................................................................................................................................. F9/R3
Clutch ...............................................................................................................................Dry dual disc (Dia: 215 mm) 8.46”
Brakes ..................................................................................................................... Mechanically actuated, sealed wet disc
Speed range (Ag tires)
Forward
1........................................................................................................................................................ 1.22 mph (1.96 kph)
2........................................................................................................................................................ 1.79 mph (2.89 kph)
3........................................................................................................................................................ 2.49 mph (4.00 kph)
4........................................................................................................................................................ 3.05 mph (4.91 kph)
5........................................................................................................................................................ 4.50 mph (7.23 kph)
6...................................................................................................................................................... 6.23 mph (10.02 kph)
7...................................................................................................................................................... 6.73 mph (10.83 kph)
8...................................................................................................................................................... 9.91 mph (15.94 kph)
9.................................................................................................................................................... 13.72 mph (22.08 kph)
Reverse
1........................................................................................................................................................ 1.26 mph (2.02 kph)
2........................................................................................................................................................ 3.15 mph (5.06 kph)
3...................................................................................................................................................... 6.93 mph (11.16 kph)

General Information
02-4 79024234 A Rev.
Power Take-Off (PTO)
Control............................................................................................................................................................ Lever and pedal
Rear PTO shaft...........................................................................................................35 mm (1.375 in) diameter - six spline
Output ........................................................................................................................................................ Clockwise rotation
Speeds @ engine rpm ........................................................................................................................................ 540 @ 2327
Mid PTO (accessory) shaft.....................................................................................................25 mm (1”) diameter 15 spline
Output ................................................................................................................................................. Clockwise rotation
Speeds @ engine revolution min-1 (rpm)................................................................................................. 2000 @ 2500
Hydraulics
Main hydraulic system
Pump.......................................................................................................................................Gear pump (Open center)
Output – maximum .................................................................................................................. 28 liters/min (7.4 gal/min)
Pressure - relief valve setting ......................................................................................................150 kgf/cm2 (2130 psi)
Rear linkage type..........................................................................................................................................Three-point hitch
Control........................................................................................................... Operated by single “position” control lever
Draft control (optional) ............................................................................................................................ Top link sensing
Lift capacity ..................................................................................................... 1100 kg (2425 lb) measured at link ends
Steering system type.............................................................................................................................................Hydrostatic
Pump................................................................................................................................................... Gear/ Flow divider
Output - maximum .................................................................................................................. 9.8 liters/min (2.6 gal/min)
Pressure - relief valve setting .....................................................................................................120 kfg/cm2 (1711 psi)
Electrical System
System voltage ........................................................................................................................... 12 volt - negative (-) ground
Battery cca @ - 18°C (OºF)........................................................................................................................................ 582 cca
Charging..................................................................................................................40 amp alternator with internal regulator
Capacities
Engine crankcase with filter........................................................................................................................ 3.6 liters (3.8 qts.)
Transmission and differential housing (including hydraulics) .................................................................... 18 liters (4.8 qts.)
Fuel tank .................................................................................................................................................... 30 liters (7.9 gals.)
Cooling system ........................................................................................................................................... 5.5 liters (5.8 qts.)
Front axle - four-wheel drive....................................................................................................................... 4.5 liters (4.7 qts.)

79024234 A Rev. 02-5
General Information
GENERAL DIMENSIONS
FIG. 5
General Dimensions
1528, ST28A, MT255B
AG Turf R-4
Front - 25x8.50-14
Rear - 12.50/80-18
Front - 24x8.50-14
Rear - 36x13.50-15
Front - 25x8.50-14
Rear - 12.50/80-18
A1 Height to Steering Wheel 1400 mm (55.1 in) 1395 mm (54.9 in) 1400 mm (55.1 in)
A2 Overall Height to ROPS 2050 mm (80.7 in) 1995 mm (78.5 in) 2050 mm (80.7 in)
B Overall Width 1360 mm (53.5 in)
width of wheel
1360 mm (53.5 in)
width of front wheel
1680 mm (66.1 in)
width of wheel
C Overall Length 2855 mm (112.4 in) 2855 mm (112.4 in) 2855 mm (112.4 in)
D Wheelbase 1665 mm (65.6 in) 1665 mm (65.6 in) 1665 mm (65.6 in)
E Minimum Ground Clearance 255 mm (10.0 in) 200 mm (7.9 in) 255 mm (10.0 in)
- Turning Radius (w/o brake) 5600 mm (220.5 in) 5600 mm (220.5 in) 5600 mm (220.5 in)
- Weight 1100 kg (2423 lb) 1040 kg (2291 lb) 1100 kg (2423 lb)
i-9553
A2
A1
B
C
D
E

02-6 79024234 A Rev.
General Information
GENERAL PRECAUTIONS FOR
SEPARATION AND REINSTALLATION
Before Operation
• Always be safety-conscious in selecting clothes to
wear and suitable tools to use.
• Before disassembly, be sure that you familiarize
yourself with the assembled condition for subsequent
reference in reassembly.
• Keep parts and tools in proper order during
operations.
• When servicing electrically live parts, be sure to
disconnect the negative battery terminal.
• To prevent oil or water leaks, use the liquid gasket as
required.
• When reassembling disassembled parts, discard
used gaskets, O-rings, or oil seals and install new
ones.
• When lifting up only the front or rear part of the
tractor, be sure to wedge the grounded wheels.
• When the tractor is jacked up, be sure to support the
entire tractor with something like a stand. Lifting it up
with a jack only is a dangerously unstable procedure.
• When replacing parts, use authorized, genuine
AGCO / Massey Ferguson / Challenger parts only.
AGCO / Massey Ferguson / Challenger assumes no
responsibility for accidents, operating problems or
damage caused by the use of imitation parts. Also,
the use of unauthorized parts will result in relatively
poor machine performance.
Precautions To Be Followed When
Installing Common Parts
Roller or ball bearings
• When a bearing is fitted in by the outer race, use an
installer which is specially designed to push only the
outer race and vice versa.
• The installer must be designed to install the bearing
on the shaft in a parallel position.
• When installing a bearing which appears the same
on both sides, install it so that the face which has the
identification number faces in a direction for easy
visual identification. All the bearings which are to be
installed in the transmission case should be placed
so that their identification number faces outward.
• If a shaft or a hole where a bearing is to be installed
has a stopper, the bearing should be pushed in
completely until it is seated against the stopper.
• Installed bearings should turn smoothly.
Oil seals
• Oil seal installer should be designed so as not to
deform the oil seals.
• During installation, be careful not to damage the lips,
and assure that it is pushed in parallel to the shaft or
hole.
• When oil seals are installed, there should be no
turnover of the lips nor dislocation of the springs.
• When a multi-lip seal is installed, the grooves
between lips should be filled with grease, not
adhesive.
• Use a lithium-based grease.
• There should be no oil or water leaks through the
installed soil seals.
O-rings
• O-rings should be coated with grease before
installing.
• Installed O-rings should have no slack or twist.
• Installed O-rings should maintain proper air tightness.

79024234 A Rev. 02-7
General Information
FIG. 6: Snap-rings
Snap-ring installers should be designed so as not to
permanently deform the snap-rings.
Installed snap-rings should be seated securely in the
groove.
Be careful not to overload the snap-ring to the extent that
it is permanently deformed.
How to install the snap-ring:
When installing a snap-ring, install it as shown in the
figure with its round edge side turned toward the part to
be retained. This round edge is formed when the
snap-ring is pressed out.
FIG. 7: Spring (roll) pins
Spring pins should be driven in properly and tightly.
Spring pins should be installed so that their seams face
the direction from which the load is applied.
The roll pins installed in the transmission or other parts
where much force is applied should be retained with wire.
FIG. 8: When installed, cotter pins should be bent
securely at the ends as shown.
FIG. 6
I3416
FIG. 7
I3417
FIG. 8
I3418

General Information
02-8 79024234 A Rev.
Bolts and Nuts
• Special bolts are installed at several locations, so be
sure not to interchange them with other bolts.
• Bolts and nuts should be tightened to their specified
torque with a torque wrench.
• When locking the bolts or nuts with wire or a lock
washer, be sure to wind the wire paying sufficient
attention to its winding direction and bend the lock
washer for secure locking.
• When locking bolts and nuts with an adhesive, apply
the adhesive on the thread and tighten securely.
• Apply an adhesive (THREE BOND TB1104) to parts
through which there is any possibility of oil leaks,
such as stud bolts and tapped-through parts.
• Each lock nut must be tightened securely.
• When tightening bolts and nuts, refer to the tightening
torque table.
After installation, each grease fitting should be filled with
grease.
• When installing grease fittings of types B and C, be
sure to turn the fitting tips in a direction that will
provide easy access for a grease gun.
Other Precautions
• Be sure not to damage any finished surfaces or parts.
• Always refrain from forcing installation.
• Each lever knob should be installed coated with an
adhesive (SUPER THREE CEMENT TB1702)
• Each contact surface should be coated with an
adhesive (THREE BOND TB1215) and tightened
evenly with bolts. Adhesive coated surfaces should
be installed within 30 minutes after application of the
adhesive.
• The contact surfaces should be flawless and free
from foreign matter, and especially from grease
before application of the adhesive.
Contact surfaces of the sleeve metal (support) and
front transmission case
Contact surfaces of the hydraulic control lever guide
and cylinder case
• Precautions for applying adhesives
The surface or the thread where an adhesive is to be
applied should be completely free of chips and oil.

79024234 A Rev. 02-9
General Information
SPEED AND REDUCTION RATIOS
FIG. 9: Traveling speeds shown.
FIG. 9
D-8179a

General Information
02-10 79024234 A Rev.
Tires
PTO Speeds & Reduction Ratio
Standard Torque Chart
FRONT REAR
Size D (mm) Size D (mm)
A (Agri tires) 25 x 8.50 - 14 657 12.50/80 - 18 978
B (R4) 25 x 8.50 - 14 657 12.50/80 - 18 978
C (Turf tires) 24 x 8.50 - 14 619 36 x 13.50 - 15 934
Input Speed
Shift
Total
Ratio
Speed
(rpm)
Max Speed
(rpm)
95% of Std.
Speed
(rpm)
10.84
21/27
27/25
0.2766
13/47 .2323 581 627 552
Mid
0.9524
20/49
49 /21
0.8 2000 2160 1900
TORQUE CHART FOR METRIC FASTENERS (ZINC COATED)
Nominal
Size
in (mm)
Strength Class -
ISO 4.6 (4T)
Strength Class -
ISO 8.8 (7T)
Strength Class -
ISO 10.9 (9T)
Torque Nm (lbf ft) Torque Nm (lbf ft) Torque Nm (lbf ft)
Min. Max. Min. Max. Min. Max.
M3
M4
M5
M6
M8
M10
M12
M16
M20
M24
M30
M36
0.5 (0.3)
1.2 (0.9)
2.2 (1.6)
4.0 (2.9)
9.5 (7.0)
19 (14)
33 (24)
84 (62)
160 (118)
280 (207)
540 (398)
950 (700)
0.7 (0.5)
1.6 (1.2)
3.0 (2.2)
5.0 (3.7)
12.5 (9.2)
25 (18)
43 (32)
110 (81)
210 (155)
360 (266)
720 (531)
1250 (922)
1.3 (0.9)
3.1 (2.3)
6.0 (4.4)
10 (7.4)
25 (18.4)
50 (37)
90 (66)
200 (148)
420 (310)
720 (531)
1400 (1033)
2500 (1844)
1.7 (1.3)
4.1 (3.0)
8.0 (5.9)
14 (10.3)
35 (26)
70 (52)
120 (89)
260 (192)
560 (413)
860 (634)
1800 (1328)
3300 (2434)
1.8 (1.3)
4.3 (3.2)
8.5 (6.3)
14 (10.3)
36 (26)
72 (53)
120 (89)
300 (221)
600 (443)
1000 (738)
2100 (1549)
3600 (2655)
2.4 (1.8)
5.7 (4.2)
1.5 (8.5)
20 (14.8)
46 (34)
96 (71)
160 (118)
400 (295)
800 (590)
1300 (2065)
2800 (2065)
4800 (3540)

79024234 A Rev. 02-11
General Information
NOTE: Above torques are for rigid joints, or joints
meeting the following conditions:
1. Damage will not occur to joined members of
an assembly.
2. It is desirable to use a higher clamping force.
3. Fastener threads are NOT lubricated prior to
assembly.
The following conditions will require a torque value
different than stated before.
1. Reduced torque required; non-parallel clamping
surfaces, thick or highly compressible gaskets are
used, or when a higher torque may damage joined
assemblies.
2. Clip nuts, weld nuts, self-tapping hardware, or any
condition that causes reduced thread engagement
will warrant a torque less than stated before.
3. Special torque values, stated in this manual, must be
strictly adhered to as stated in the specific operation.