Charge Pump - Simplicity 1691682 Service & Repair Manual

7 Transmission Repair
7D Sauer-Sundstrand BDU-10L-258

Charge Pump

DISASSEMBLY
Note: Repairing the charge pump will require the
hydro pump to be removed from the transaxle assembly.
Important: The correct charge pump orientation is deter-
mined by the rotation of the pump shaft (clockwise or
counter-clockwise). Before removing the charge pump,
make note of, or mark its position to simplify the
reassembly process.
1. Using a 5 mm internal hex wrench, remove the two
screws holding the charge pump cover on.
2. Remove the charge pump cover and O-ring. Avoid
turning or twisting the charge cover during removal,
or damage to the charge relief spring may occur.
3. Remove the charge pump gerotor assembly.
4. Remove the charge pump drive pin, spacer plate and
O-ring. Make note of, and/or mark the top and/or bot-
tom of the spacer plate.
5. Remove the charge relief valve spring and ball.
6. Inspect the gerotor assembly, charge pump cover,
and spacer plate for abnormal wear, damage or
foreign material. Inspect the charge relief valve ball
and spring. Inspect the charge relief valve seat in the
center section for damage or foreign material.
ASSEMBLY
1. Prior to reassembly of the charge pump, apply a
small quantity of petroleum jelly to the l.D., O.D., and
faces of the gerotor assembly.
Note: Improper assembly of the charge relief valve
spring and ball, or the incorrect orientation of the spacer
plate and cover will cause a priming failure. If assembled
properly, the charge pressure should be maintained at
25 to 70 PSI at 3000 RPM pump speed.
2. Install the charge relief valve spring and ball.
Note: The charge relief spring must enter the recessed
hole in the spacer plate.
3. Install a new O-ring and the spacer plate onto the
aligning pins.
Note: Correct installation of the spacer plate will not
have O-rings contacting each other.
4. Install the charge pump drive pin.
5. Install the gerotor assembly.
6. Install a new O-ring and charge pump cover.
7. Install two bolts and torque evenly to 7-10 ft. lbs.
Figure D-12. Charge Pump Cover Orientation
C
A
B
Figure D-13. Charge Pump Assembly
A. Capscrew
B. Seal
C. Pump Housing
D. Gerotor
7 - 52
E
F
G
F
E
D
E. Dowel Pin
F. O-Ring
G. Spacer Plate