PDF Service Manual BOBCAT B250 B Series Backhoe Loader - 4 MB
This is the complete service manual for the Bobcat B250 B Series Backhoe Loader with serial numbers starting from 572911001.
It contains detailed repair and maintenance procedures for every aspect of the machine.
Technicians will find comprehensive instructions for the engine, hydraulics, transmission, and electrical systems.
Using this manual is the best way to ensure that all repairs are performed correctly and to factory specifications, maximizing the machine's performance and lifespan.
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--- Page 1 ---
B250
Service
Manual
B Series
S/N 572911001 & Above
Doosan purchased Bobcat Company from Ingersoll-Rand Company in
2007. Any reference to Ingersoll-Rand Company or use of trademarks,
service marks, logos, or other proprietary identifying marks belonging
to Ingersoll-Rand Company in this manual is historical or nominative
in nature, and is not meant to suggest a current affiliation between
Ingersoll-Rand Company and Bobcat Company or the products of
either.
6903864 (6-12) Printed in U.S.A. ©Bobcat Company 2006
--- Page 3 ---
SAFETY INSTRUCTIONS The following publications provide information on the
safe use and maintenance of the Bobcat machine and
attachments:
Safety Alert Symbol
• The Delivery Report is used to assure that complete
This symbol with a warning statement means: instructions have been given to the new owner and
“Warning, be alert! Your safety is involved!” that the machine is in safe operating condition.
Carefully read the message that follows.
• The Operation & Maintenance Manual delivered with
the machine or attachment contains operating
information as well as routine maintenance and
service procedures. It is a part of the machine and can
WARNING be stored in a container provided on the machine.
Replacement Operation & Maintenance Manuals can
be ordered from your Bobcat dealer.
Instructions are necessary before operating or
servicing machine. Read and understand the • Machine signs (decals) instruct on the safe operation
Operation & Maintenance Manual, Operator’s and care of your Bobcat machine or attachment. The
Handbook and signs (decals) on machine. Follow signs and their locations are shown in the Operation
warnings and instructions in the manuals when & Maintenance Manual. Replacement signs are
making repairs, adjustments or servicing. Check for available from your Bobcat dealer.
correct function after adjustments, repairs or
service. Untrained operators and failure to follow • An Operator’s Handbook fastened to the operator
instructions can cause injury or death. cab. It’s brief instructions are convenient to the
W-2003-0903 operator. The handbook is available from your dealer
in an English edition or one of many other languages.
See your Bobcat dealer for more information on
translated versions.
WARNING • The AEM Safety Manual delivered with the machine
gives general safety information.
Warnings on the machine and in the manuals are for
your safety. Failure to obey warnings can cause • The Service Manual and Parts Manual are available
injury or death. from your dealer for use by mechanics to do shop-
W-2044-1285 type service and repair work.
• The Loader Backhoe Operator Training Course is
available through your local dealer or at
IMPORTANT www.training.bobcat.com or www.bobcat.com.
This course is intended to provide rules and practices
of correct operation of the Loader Backhoe.
This notice identifies procedures which must be
followed to avoid damage to the machine.
I-2019-0284
• The Loader Backhoe Safety Video is available from
your Bobcat dealer or at www.training.bobcat.com
or www.bobcat.com.
SI LB-0206 SM
B250 Bobcat Loader Backhoe
V Service Manual
--- Page 4 ---
SAFETY &
SAFETY & MAINTENANCE
MAINTENANCE
AIR CLEANER SERVICE . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-80-1
Daily Check . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-80-1
Replacing The Air Filter Element . . . . . . . . . . . . . . . . . . . . 10-80-1
ALTERNATOR BELT . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-160-1
Adjusting The Alternator Belt . . . . . . . . . . . . . . . . . . . . . . 10-160-1
APPROVED LIFT ARM SUPPORT DEVICE . . . . . . . . . . . . . 10-20-1
Installing The Approved Lift Arm Support Device . . . . . . . 10-20-1
Removing The Approved Lift Arm Support Device . . . . . . 10-20-2
DRIVE
AXLE TOE-IN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-60-1 SYSTEM
Adjustment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-60-1
BOOM LOCK PIN . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-140-1
Engaging And Disengaging The Pin . . . . . . . . . . . . . . . . 10-140-1
BOB-TACH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-150-1
Inspection And Maintenance . . . . . . . . . . . . . . . . . . . . . . 10-150-1 ELECTRICAL
SYSTEM &
ENGINE COOLING SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . 10-90-1 ANALYSIS
Checking Coolant Level . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-90-1
Cleaning The Cooling System . . . . . . . . . . . . . . . . . . . . . . 10-90-1
Coolant Replacement . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-90-2 ENGINE
SERVICE
ENGINE COVER. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-30-1
ENGINE LUBRICATION SYSTEM . . . . . . . . . . . . . . . . . . . . 10-110-1
Checking Engine Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-110-1 SPECIFICATIONS
Oil Chart. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-110-1
Replacing The Oil And Filter . . . . . . . . . . . . . . . . . . . . . . 10-110-2
FRONT AXLE . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-130-1
Checking Oil Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-130-1
Draining Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-130-1
FUEL SYSTEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-100-1
Filling The Fuel Tank . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-100-1
Fuel Filter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-100-1
Fuel Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-100-1
Removing Air From The Fuel System . . . . . . . . . . . . . . . 10-100-3
HYDRAULIC/HYDROSTATIC SYSTEM . . . . . . . . . . . . . . . . 10-120-1
Checking And Adding Fluid . . . . . . . . . . . . . . . . . . . . . . . 10-120-1
Cleaning The Cooler . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10-120-2
Replacing Hydraulic Fluid . . . . . . . . . . . . . . . . . . . . . . . . 10-120-3
Replacing Hydraulic/Hydrostatic Filter . . . . . . . . . . . . . . . 10-120-2
Continued On Next Page
B250 Bobcat Loader Backhoe
10-01 Service Manual
--- Page 5 ---
TOWING THE LOADER BACKHOE Figure 10-50-3
Procedure
Place blocks in front and behind rear wheels.
1
Figure 10-50-1
1
1
2
1
P-42732
1
Rotate the tow valve (Item 1) [Figure 10-50-3]
counterclockwise approximately 3 turns.
P-33314 Figure 10-50-4
Remove the 4 mo unting bolts (Item 1) and floor cover
(Item 2) [Figure 10-50-1].
Figure 10-50-2
1
1
2 1
P-49089
Loosen the 2 jam nuts (Item 1) and turn the parking brake
linkage (Item 2) [Figure 10-50-4] approximately 2 turns.
(Record the exact amount of turns on the parking brake
P-42731 linkage (Item 2). When putting the machine back in
service, you must turn the parking brake linkage back to
its original setting.)
Loosen the tow valve (Item 1) [Figure 10-50-2].
To prevent damage to the l oader backhoe hydrostatic
system, the loader backhoe must be towed only a short
distance at s low speed. (Example: Moving the loader
backhoe onto a transport vehicle.
The towing chain (or cable) must be rated at 1-1/2 times
the weight of the loader. (See LOADER BACKHOE
SPECIFICATIONS on Page SPEC-10-1.)
NOTE: Be sure to retighten the tow valve and readjust
the parking brake linkage before operating the
loader backhoe after towing.
B250 Bobcat Loader Backhoe
10-50-1 Service Manual
--- Page 6 ---
ENGINE COOLING SYSTEM (CONT’D) NOTE: The loader backhoe is f actory filled with
propylene glycol. DO NOT mix propylene
Coolant Replacement (Cont’d) glycol with ethylene glycol.
Figure 10-90-4 Premixed the coolant; 47% water and 53% p ropylene
glycol.
One gallon and 1 pint (4,3 L) of pr opylene glycol mixed
with 1 gallon (3,8 L) of water is the correct mixture of
coolant to provide a -34° F (-37° C) freeze protection.
Use a refractometer to check the condition of propylene
1 glycol in your cooling system.
Fill the radiator with the premixed coolant until it is full.
Install the radiator cap.
Fill the coolant recovery tank to the full mark.
P-47707 Run the engine at idle speed for about 5 to 10 minutes to
remove the air from the cooling system.
Open the radiator drain valve (Item 1) [Figure 10-90-4] at
Stop the engine. Check the coolant level in the coolant
the right side of the r adiator. Drain the coolant into a
recovery tank and add coolant as needed.
container.
Figure 10-90-5
1
P-47706
Open the engine block drain valve (Item 1) [Figure 10-
90-5] (If Equipped) and drain the coolant into a container.
(If not equipped with a drain valve, remove the hose from
the fitting to drain the block.)
After all the coolant is removed, close both drain valves.
Recycle or dispose of coolant in an environmentally safe
manner.
Mix the coolant in a separate container. (See LOADER
BACKHOE SPECIFICATIONS on P age SPEC-10-1 for
correct capacity.)
B250 Bobcat Loader Backhoe
10-90-3 Service Manual
--- Page 7 ---
HYDRAULIC/HYDROSTATIC SYSTEM Figure 10-120-2
Checking And Adding Fluid
Use only recommended fluid in the hydraulic system.
(See HYDRAULIC/HYDROSTATIC FLUID 1
SPECIFICATIONS on Page SPEC-50-1)
Put the loader backhoe on a flat level surface.
Remove the bo om lock pin. (See BOOM LOCK PIN on
Page 10-140-1.)
Remove the swing lock pin. (See SWING LOCK PIN on
Page 10-190-1.)
P-47627
Retract the arm and bucket cylinders, put the bucket on
the ground.
Remove the fill cap (Item 1) [Figure 10-120-2].
Lower the lift arms and tilt the Bob-Tach fully back.
Figure 10-120-3
Stop the engine.
Figure 10-120-1
P-47628
P-47626
Check the condition of the fill strainer [Figure 10-120-3].
The screen must be installed in the fill neck when adding
oil.
Check that the fluid level in the sight gauge [Figure 10-
120-1] is 2/3 to 3/4 full. Add the fl uid as needed to bring the level on the s ight
gauge to 2/3 to 3/4 full.
Install the fill cap (Item 1) [Figure 10-120-2].
WARNING
Always clean up spilled fuel or oil. Keep heat, flames,
sparks or lighted tobacco away from fuel and oil.
Failure to use care around combustibles can cause
explosion or fire which can result in injury or death.
W-2103-1285
B250 Bobcat Loader Backhoe
10-120-1 Service Manual
--- Page 8 ---
ALTERNATOR BELT Figure 10-160-2
Adjusting The Alternator Belt
WARNING
Never work on a machine with the lift arms up unless
the lift arms are secured by an approved lift arm
support device. Failure to us e an approved lift arm
support device can allow the lift arms or attachment
to fall and cause injury or death.
W-2059-0598
P-47622
Raise the lift arms and install the approved lift arm
support device. (See Installing The Approved Lift Arm
Support Device on Page 10-20-1.) Move the alternator until the bel t has 5/16 in. (8,0 mm)
movement at the middle of the belt span with 15 lb. (66 N)
Stop the engine and engage the parking brake. of force [Figure 10-160-2].
Remove the side cover from the left side. Tighten the adjustment and mo unting bolts (Item 1)
[Figure 10-160-1].
Figure 10-160-1
1
1
P-47623
Loosen alternator mounting and adjustment bolts (Item
1) [Figure 10-160-1].
B250 Bobcat Loader Backhoe
10-160-1 Service Manual
--- Page 9 ---
SWING LOCK PIN Figure 10-190-2
Engaging The Swing Lock Pin
NOTE: When using both the boom loc k pin a nd the 2
swing lock pin, the boom lock pin should be
installed first.
NOTE: Attachments wider than a 16 in . backhoe
bucket can contact the stabilizer when the
backhoe boom is side shifted and fully swung
to the side. These attachments must be
removed before engaging the swing lock pin.
1
Figure 10-190-1
P-47700
1 Move the boom to the left or right, stop the engine,
engage the parking brake and exit the loader backhoe.
Remove the r etainer pin (Item 1) and install the s wing
lock pin (Item 2) [Figure 10-190-2], by lowering it into the
mating boss on the swing frame.
Figure 10-190-3
P-47699 1
With the swing lock pin (Item 1) [Figure 10-190-1] in the
storage position, engage the parking brake, start the
engine.
WARNING
P-47596
AVOID CRUSHING HAZARD
• Do not lean over controls.
• Engage and disengage the boom pin and swing Install the retainer pin (Item 1) [Figure 10-190-3].
lock pin lock with the engine off.
• Do not ope rate the loader controls from outside
the operator’s area.
W-2425-0302
B250 Bobcat Loader Backhoe
10-190-1 Service Manual
--- Page 10 ---
HYDRAULIC SYSTEM INFORMATION (CONT'D)
Troubleshooting
WARNING
The following troubleshooting chart is provided for
assistance in locating and correcting problems which are Check for correct function after adjustments, repairs
most common. Many of the recommended procedures or service. Failure to make correct repairs or
must be done by authorized Bobcat Service Personnel adjustments can cause injury or death.
only. W-2004-1285
PROBLEM CAUSE
The hydraulic system will not operate. 1, 2, 3, 6
The transmission warning light comes ON when hydraulics are operating. 1, 2
Slow hydraulic system action. 1, 2, 4, 8
Hydraulic action is not smooth. 1, 3, 4, 5
Lift arms go up slowly at full engine RPM. 1, 2, 4, 5, 6, 7
The lift arms come down with the lever in neutral position. 7, 8, 9
KEY TO CORRECT THE CAUSE
1. The fluid level is not correct.
2. The hydraulic pump has damage.
3. Relief valve is not at the correct pressure.
4. Suction leak on the inlet side of the hydraulic pump.
5. Fluid is cold. Wrong viscosity fluid. (See Specifications on Page SPEC-50-1.)
6. Using the loader for more than its rated capacity.
7. Internal leak in the lift cylinder.
8. External leak from the cylinder(s).
9. Damaged lift spool.
B250 Bobcat Loader Backhoe
20-10-5 Service Manual
--- Page 11 ---
ARM CYLINDER (CONT’D) Figure 20-20-26
Assembly (Cont’d) 1
Figure 20-20-24 2
2
P-50080
1
Clean and dry the cylinder rod threads. Install the piston
P-50081 (Item 1). Apply Loctite™ 242 or equivalent to the cylinder
rod threads and install the nut (Item 2) [Figure 20-20-26].
Install the he ad gland (Item 1) and spacer (Item 2) Installation: Tighten the nut to 10 5 ft.-lb. (142 N•m)
[Figure 20-20-24] onto the cylinder rod. torque.
Figure 20-20-25 Figure 20-20-27
3
2
3
1 1
2
P7430 P-50083
Install the O-ring (Item 1) and seal (Item 2) onto the Install the rod assembly (Item 1), into the housing (Item
piston (Item 3) [Figure 20-20-25]. 2) and tighten the head gland (Item 3) [Figure 20-20-27].
B250 Bobcat Loader Backhoe
20-20-9 Service Manual
--- Page 12 ---
BOOM CYLINDER (CONT’D) Assembly
Disassembly (Cont’d) Wash the cylinder parts in solvent and dry with
compressed air.
Figure 20-21-27
Inspect the cylinder parts for wear or damage. Replace
1 any worn or damaged parts.
Lubricate all O-rings and seals with clean hydraulic oil
during installation.
Figure 20-21-28
2 1
P-50082
Remove the wiper (Item 1) and rod seal (Item 2) [Figure 2
20-21-27] from the head gland.
P-50082
Install the wiper (Item 1) and rod seal (Item 2) [Figure
20-21-28] in the head gland.
Figure 20-21-29
1
3 2
P74227
Install the O-ring (Item 1), backup washer (Item 2) and O-
ring (Item 3) [Figure 20-21-29] on the head gland.
B250 Bobcat Loader Backhoe
20-21-9 Service Manual
--- Page 13 ---
SWING CYLINDER (CONT’D) Bushing Removal And Installation
Assembly (Cont’d) Inspect all bushings and replace as necessary.
Figure 20-22-25 Figure 20-22-27
1 1
1
P-50667 P-50660
Install the rod assembly (Item 1) [Figure 20-22-25] into Remove the bushings (Item 1) [Figure 20-22-27].
the housing.
NOTE: For correct assembly note the direction of the
Figure 20-22-26 bushing as it is removed.
Installation: Install the bushings until they are flush with
the support.
1 Figure 20-22-28
1
P-50666
Use a gla nd nut wrench (MEL1075) to tighten the head
gland (Item 1) [Figure 20-22-26].
P-50663
Remove the bushing (Item 1) [Figure 20-22-28].
NOTE: For correct assembly note the direction of the
bushing as it is removed.
Installation: Install the bushing until they are flush with
the support.
B250 Bobcat Loader Backhoe
20-22-9 Service Manual
--- Page 14 ---
BUCKET CYLINDER (CONT’D) Assembly
Disassembly (Cont’d) Wash the cylinder parts in solvent and dry with
compressed air.
Figure 20-23-26
Inspect the cylinder parts for wear or damage. Replace
1 any worn or damaged parts.
Lubricate all O-rings and seals with clean hydraulic oil
during installation.
Figure 20-23-27
2 1
P-50082
Remove the wiper (Item 1) and rod seal (Item 2) [Figure 2
20-23-26] from the head gland.
P-50082
Install the wiper (Item 1) and rod seal (Item 2) [Figure
20-23-27] in the head gland.
Figure 20-23-28
1
3 2
P74227
Install the O-ring (Item 1), backup washer (Item 2) and O-
ring (Item 3) [Figure 20-23-28] on the head gland.
B250 Bobcat Loader Backhoe
20-23-9 Service Manual
--- Page 15 ---
STABILIZER CYLINDER (CONT’D)
Disassembly (Cont’d)
Figure 20-24-24
2
1
P-50625
Remove the wiper seal (Item 1) and rod seal (Item 2)
[Figure 20-24-24].
B250 Bobcat Loader Backhoe
20-24-9 Service Manual
--- Page 16 ---
TILT CYLINDER Figure 20-30-2
Checking
Remove attachment from the Bob-Tach.
Lower the l ift arms to the g round, fully retract the tilt
2
cylinders.
Stop the engine, engage the parking brake.
Operate the control lever to relieve hydraulic pressure.