Replacing the hydro pump, M48 tank – Cub Cadet M48 User Manual
Page 10

M48 Tank
6
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.
NOTE: It may be necessary to over-shoot 300 
PSI slightly, then open the valve to reduce pres-
sure to 300 PSI.
4.24. Take note of the reading on the flow meter por-
tion 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.
4.26. Subtract the 1,100 PSI flow reading from the 300
PSI flow reading. The resulting figure is called 
“flow droop”.
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 war-
ranty period, replace the pump if it does not per-
form as specified and all other factors have been 
eliminated.
4.29. If a hydro pump requires repair, refer to Hydro-
Gear publication “BLN-51337” for complete ser-
vice 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.
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 bat-
tery 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.
Figure 4.23
FLOW
300 PSI
10 GPM
BUILD PRESSURE
CLOSE VALVE TO
SPINNING
CONTROL 
CONSOLE INSET:
 3600 RPM
Figure 4.25
1100 PSI
9 GPM
VALVE CLOSED 
FURTHER
Figure 5.5
REMOVE DEBRIS SCREEN
