Rayco C275, Operator, Service, Maintenance Manual

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Series 42 Adjustments and Minor Repairs
4.12 Loop Flushing Valve
The loop flushing function consists of the loop flush-
ing shuttle valve and the loop flushing relief valve. The
assemblies may be removed for cleaning and instal-
lation of new O-rings. The relief valve poppet may be
exchanged for one with a different flow rating, but the
relief valve shims should not be changed out unless
specifically instructed so by Sauer-Sundstrand. The
function also can be defeated.
Loop Flushing Valve
1. Remove the loop flushing valve plug from the
pump housing [11/16 in Hex]. Remove the O-ring
from the plug.
2. Remove the loop flushing valve spool assembly
from the housing.
3. Inspect the parts for damage or foreign material.
The centering spring must be securely retained to
the spool by the washer.
4. Install the loop flushing valve spool assembly into
its bore. Install a new O-ring on the loop flushing
plug and install [27-47 Nm (20-35 ft•lbf)].
Loop Flushing Relief Valve
1. Remove the loop flushing relief valve internal hex
plug [5/8 in Hex] from the pump housing. Remove
the O-ring from the plug.
2. Remove the spring and poppet from the housing.
3. Do not alter the shims which are installed be-
tween the spring and valve plug, or interchange
parts with another valve. Inspect the poppet and
mating seat in the housing for damage or foreign
material. Inspect the orifice in the valve poppet.
4. Install a new O-ring on the valve plug. Reinstall
the poppet, spring, shims, and plug (with O-ring)
into the pump housing [15-34 Nm (15-25 ft•lbf)].
Defeating Loop Flushing
1. Remove the loop flushing valve from the pump
housing.
2. Install the defeat spool into the spool bore in the
housing. Install the plain plug with O-ring into the
housing [11/16 in Hex], and torque [27-47 Nm
(20-35 ft•lbf)].
3. Remove the charge relief valve (these parts are
not necessary).
4. Install the plain hex plug with O-ring into the end
cap [5/8 in Hex], and torque [15-34 Nm (15-25
ft•lbf)].
Spring
Poppet
Shims
O-Ring
O-Ring
Loop Flushing Relief
Plug (Defeat)
O-Ring
Loop Flushing
Plug (Defeat)
Defeat
Spool
O-Ring
Loop
Flushing
Plug
Loop
Flushing
Spool
Assembly
Loop Flushing
Relief Plug
Loop Flushing Valve and Loop Flushing Defeat
Components
E100018 E