Cub Cadet M48 User Manual
Service Manual
Cub Cadet M48 Tank
IMPORTANT: READ SAFETY RULES AND INSTRUCTIONS CAREFULLY
This Service Manual is not a substitute for the Operator’s Manual. You must read, understand
and follow all of the directions in this manual as well as the Operator’s Manual before working
on this power equipment.
CUB CADET LLC, P.O. BOX 361131, CLEVELAND, OH 44136-0019
PRINTED IN USA
FORM NO.769-00966
(11/2003)
TABLE OF CONTENTS
M48 Tank..........................................................................................................1
About this Section.............................................................................................1
Changes for ‘03 and ‘04....................................................................................1
Drive System Adjustment..................................................................................1
Hydro Pump Testing..........................................................................................4
Hydro Pump Replacement................................................................................6
Hydro Pump Motor Replacement......................................................................10
Brake Linkage Adjustment ................................................................................13
M72 Tank..........................................................................................................16
Other Tank Features.........................................................................................19
Kohler EFI.........................................................................................................23
EFI Controls......................................................................................................26
M48 Tank
M48 Tank
1. ABOUT THIS SECTION:
The M48 is part of the Cub Cadet Commercial Tank
Series. The 2004 model year M48 is very similar to
The 2001 model year Tank. Earlier versions of this
machine have been covered in the “2001 Cub Cadet
Commercial Technical Handbook”: Form #770-
10528.
2. CHANGES FOR ‘03 AND ‘04
• New hydro motor frame assembly
• New hydro motors
• New brakes and brake linkages
• Finer increments of height adjustment
• Different choice of engines
• Features of the 72” TANK
The content of this section is intended to detail
changes in service techniques that have occurred
since the introduction of the M Series.
3. DRIVE SYSTEM ADJUSTMENT
3.1. Prior to making any adjustments to the drive system, inspect the hydro control linkages, drive
belt, brake linkage, tires, fluid, and filter.
3.2. The hydraulic reservoir and filter are accessible
beneath the seat. See Figure 3.2.
RESERVOIR
OIL FILTER
BATTERY
3.3. The hydraulic fluid level should be at the second
hole in the filler neck of the reservoir.
See Figure 3.3.
FIRST HOLE
SECOND HOLE
FLUID LEVEL
Figure 3.3
NOTE: It is very important that the hydraulic oil
does not become contaminated. Clean the surrounding area thoroughly prior to opening any
part of the hydraulic system.
NOTE: The hydraulic drive system contains
roughly 3.25 gal. of SAE 20W50 motor oil having
an API rating of SJ-CD or better. Hydraulic
Drive System Fluid Plus (P/N: 737-3121 gal.)
is an acceptable premium alternative.
NOTE: Complete draining and filling instructions
are contained in the “Operator’s and Service
Manual”.
3.4. Tracking is effected by the circumference of the
rear tires, and the amount of drag produced by
the front tires.
• Rear tire pressure may be adjusted within the
range of 8-10 PSI to achieve equal rear tire circumference.
Figure 3.2
• Front tire pressure should be within the range
of 20-25 PSI.
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M48 Tank
3.5. For complete brake adjustment procedures,
refer to the “Brake Adjustment” section of this
manual. For the purpose of tracking, insure that
the brake linkage bellcranks and rods are well
lubricated, not damaged, and work as intended.
See Figure 3.5.
BRAKE CONNECTING
ROD
Brake
Link
REAR BRAKE
ARM ASSEMBLY
BELLCRANK
MOUNTING
SHAFT
Figure 3.5
3.6. To check for brake drag, open the the relief valve
on each hydro pump. With the parking brake
released, both wheels should rotate with hand
pressure. See Figure 3.6.
3.7. If in doubt about the source of brake drag, disconnect the brake link rod from the actuator arm
on the brake assembly. The actuator arm
should return to center, releasing the brakes.
See Figure 3.7.
BRAKE LINK
BRAKE ACTUATOR
ARM
Figure 3.7
3.8. Check the condition of the belt tensioner and
belt that drives the hydro pumps. See Figure 3.8.
OPEN
HYDRO PUMP
HYDRO RELIEF VALVE
Figure 3.6
NOTE: Some hydraulic system drag will be
present, but a dragging brake will be immediately apparent.
DRIVE BELT
TENSIONER
Figure 3.8
3.9. Before making neutral control and tracking
adjustments, make sure the relief valves on both
hydro pumps are fully closed.
3.10. To check neutral control, safely lift and support
the rear wheels of the Tank.
3.11. Start the engine, and release the parking brake.
Do not move the lap bars from the neutral position. If either wheel rotates, neutral control
adjustment will be necessary. Turn off the
engine.
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M48 Tank
3.12. If adjustment is necessary, remove the cutting
deck.
3.13. Inspect the return to neutral cylinders, rods, and
bellcranks of the hydro control linkages.
• The bellcranks should pivot easily without too
much play.
• The rods should not be bent, and the rod ends
should not be loose.
NOTE: The rod end and jam nut at the rear of
each connector rod have left hand threads. A
lock washer is placed between the control input
arm on the hydro pump and the rod end.
NOTE: The rod end and jam nut at the front of
each connector rod have right hand threads. A
spacer fits between each control hub assembly
(bellcrank) and the front rod end that connects to
it.
• The return to neutral cylinders should both work
as advertised. See Figure 3.13.
3.14. Loosen the jam nuts at each end of the hydro
control link rods, and rotate the rods to lengthen
or shorten them. See Figure 3.14.
Figure 3.14
3.15. Start the engine and release parking brake to
test, then turn the engine off to make the adjustment.
3.16. Tighten the jam nuts against the rod ends when
adjustment is complete, and make a final test to
confirm.
RETURN TO NEUTRAL
CYLINDER (RIGHT)
Figure 3.13
NOTE: Remove the control console to gain
access to the return to neutral cylinder.
3.17. After neutral control is correctly adjusted, set the
travel stops to achieve correct tracking and
adjust the lap bars for operator comfort.
See Figure 3.17.
LAP BAR
MOUNTING
HANDLE
CLAMP
BOLTS
JAM
NUT
LAP BAR TRAVEL
STOP BOLT
Figure 3.17
NOTE: The clamp bolts for the lap bar mounting
handle can be used to adjust the amount of force
required to move the lap bars into or out of the
neutral slot.
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M48 Tank
3.18. If one side does not drive as effectively as the
other, test the output of the hydro pump to determine if the problem lies in the pump or the hydro
motor. By the process of elimination, if performance is lacking, brake drag is eliminated,
adjustment is correct, and the pump is O.K.,
then the problem is the motor. Pressure and
flow tests will be used to determine if the pump
is the the source of the problem.
4. TESTING HYDRO PUMP OUTPUT
NOTE: The log splitter hydraulic test kit is used
for this set of flow and pressure tests.
4.1. Safely lift and support the rear of the M48.
4.2. If the cutting deck is currently on the unit,
remove it.
4.3. Remove the rear wheels using a 3/4” socket.
See Figure 4.3.
4.4. Thoroughly clean the area surrounding any
hydraulic fittings to be loosened or removed.
4.5. If the unit has been run recently, allow it to cool
before doing loosening any hydraulic fittings.
WARNING: Hot hydraulic fluid can cause serious burns.
WARNING: Release of pressurized hydraulic
fluid can cause serious of fatal injury.
4.6. Open the relief valve on the hydro pump that is
to be tested. This will relieve any residual
hydraulic pressure.
4.7. Confirm that the hydraulic pressure has been
relieved by rotating the brake drum / hub assembly. If the it will not rotate, confirm that the brake
is released and that the brake linkage is not
bound.
4.8. Install a 1/2” JIC double male coupler in one end
of the 18” hydraulic line in the test kit. Install a
90 deg. 1/2” JIC double male elbow in the other
end. See Figure 4.8.
1/2” JIC COUPLER
VALVE
PRESSURE
GUAGE
FLOW
METER
18” HYDRAULIC
LINE
1/2” JIC
ELBOW
HIGH PRESSURE LINES:
TOP: in-forward / out-reverse
BOTTOM: out-forward / in-reverse
Figure 4.3
NOTE: The fittings on the lines that connect the
hydro pumps to the hydro motors are 1/2” JIC.
NOTE: 7/8” and 13/16” wrenches will be needed
for this test. A 1” wrench may be needed to hold
the connector that joins the JIC line connection
to the O ring connection on the hydro motor.
BRAKE DRUM
HYDRO MOTOR
Figure 4.8
4.9. Position a catch pan beneath the hydro motor.
Have the hydraulic pressure and flow test kit and
two 1/2” JIC plugs within reach.
NOTE: The fittings on the ends of the test kit are
all 1/2” JIC.
4.10. Disconnect the upper line from the hydro motor
and quickly install a 1/2” JIC plug in the line. It
only needs to be finger tight.
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NOTE: The test can be performed at either line
between the pump and the motor. The top line
on the motor is the in line from the pump when
driving forward. The linkage has more travel in
forward than it does in reverse, so the test is
most easily done on the top line of the pump,
driving the pump in the forward direction forward.
4.11. Connect the flow meter end of the test kit to the
hydro motor.
4.12. Remove the plug from the line coming from the
outboard port on the hydro pump. Use the 18”
test kit line to connect the pressure gauge end of
the hydraulic test kit to the line coming from the
hydro pump. See Figure 4.12.
M48 Tank
4.15. Remove the stop bolt that sets the end of the
travel of the lap bar that controls the hydro pump
to be tested. See Figure 4.15.
JAM NUT
STOP BOLT
Figure 4.15
Figure 4.12
4.13. Tighten all the fittings.
4.14. Insure that no unsafe conditions will result from
starting the engine and operating the drive system.
CAUTION: The technician will be exposed to
moving parts during this procedure. They
should not reach past or around any moving
parts during this test, nor should they place
themselves in any position where a loss of footing or balance might bring them into contact with
rotating components. Loose hair or garments
should be secured to avoid the possibility of
entanglement with rotating components.
4.16. Confirm that the valve on the test kit is fully
open.
4.17. Start the engine and purge the hydraulic sys-
tem as follows:
4.18. Cycle the lap bar from full forward to full reverse
5 times at 10 second intervals.
4.19. Close the relief valve on the hydro pump and
repeat the cycling process to purge any remaining air from the system.
4.20. Check for and repair any leaks.
4.21. Check the fluid level in the hydraulic reservoir.
Top it up if necessary.
4.22. Continue to operate the drive system to warm-up
the hydraulic fluid.
NOTE: Performing the test with cold fluid will
make a significant difference in the flow readings
obtained. The test will not be valid.
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M48 Tank
4.23. When the fluid is between 160-210 deg. f.
(71-90 deg. c.) apply full forward drive pressure
to the lap bar with the engine running at full
speed (3600 RPM) while an assistant closes the
valve to the point where pressure reaches 300
PSI (21 Bar.). See Figure 4.23.
CONTROL
CONSOLE INSET:
3600 RPM
SPINNING
FLOW
300 PSI
10 GPM
CLOSE VALVE TO
BUILD PRESSURE
Figure 4.23
4.27. Interpretation: flow droop greater than 1.5 GPM
indicates a pump that is not performing as well
as it should.
NOTE: A blocked filter may account for some
loss of performance.
4.28. Within the two year Cub Cadet Commercial warranty period, replace the pump if it does not perform as specified and all other factors have been
eliminated.
4.29. If a hydro pump requires repair, refer to HydroGear publication “BLN-51337” for complete service instructions.
4.30. If the hydro pump and all other factors are O.K.,
replace the hydro motor.
NOTE: The hydro motor is not serviceable.
Replace it as a unit if it fails.
NOTE: It may be necessary to over-shoot 300
PSI slightly, then open the valve to reduce pressure to 300 PSI.
4.24. Take note of the reading on the flow meter portion of the test kit when the pressure gauge
reads 300 PSI.
4.25. Continue closing the valve until the pressure
reading reaches 1,100 PS I (76 bar.). Take note
of the flow reading. See Figure 4.25.
9 GPM
1100 PSI
Figure 4.25
VALVE CLOSED
FURTHER
5. REPLACING THE HYDRO PUMP
5.1. If the cutting deck is currently on the unit,
remove it.
5.2. Safely lift and support the rear of the tank.
5.3. Remove the rear wheels using a 3/4” socket.
5.4. Tilt the seat up, and disconnect the negative battery cable.
5.5. Remove the screen that covers the opening over
the cooling fans on the hydro pump to be
removed using a 3/8” wrench. See Figure 5.5.
REMOVE DEBRIS SCREEN
4.26. Subtract the 1,100 PSI flow reading from the 300
PSI flow reading. The resulting figure is called
“flow droop”.
Figure 5.5
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