Simplicity 1691766, Service & Repair Manual

Page: 193 / 240

Bypass Valve
1. Remove the bypass valve plug with a 9/16” hex
wrench. Remove the plug and valve spool.
2. Remove the valve spring from the transmission cen-
ter section.
3. Inspect the valve and mating bore in the center sec-
tion for damage or foreign material. The spool must
move freely in its bore. Replace the valve spool O-
ring.
4. Retain the spring to the spool with petroleum jelly.
Reinstall the valve spool (with spring) and plug (with
O ring) into the center section. Torque the plug to 8 to
20 ft.lbs. (11 to 27 Nm).
5. Depress the bypass valve several times to insure that
the valve operates smoothly and fully closes.
Figure D-11. Bypass Valve Removal
7 - 51
7 Transmission Repair
7D Sauer-Sundstrand BDU-10L-258
Charge Check Valves
1. Remove the check valve plug with a 1/4” internal hex
wrench.
2. Remove the valve spring and check ball from the
transmission center section or pump end cap.
CAUTION Do not allow the check balls to fall into
the closed loop passages in the center section or
end cap.
3. Inspect the check balls and mating seats in the cen-
ter section or end cap for damage or foreign material.
4. Lay the transmission or pump on its side and reinstall
the check ball, spring, and plug (with O-ring) into the
center section or end cap. Be certain the check ball
does not fall into the closed loop passage. Torque the
plug to 15 to 35 ft.lbs. (28 to 47 Nm). Turn the unit
over and repeat for the other check valve.
Figure D-8. Check Valve Removal/Installation
Figure D-9. Check Valve Diagram
A. Check Ball Assembly
B. Poppet Assembly
C. Check Valve Plug D. Rubber O-Ring
E. Spring F. Check Ball
G. Poppet H. Check Valve Plug
A
B
C
D
E
F
G
E
D
H
Poppet Check Valve Ball
Figure D-10. Check Valves