Rayco C275, Operator, Service, Maintenance Manual, Page: 82 / 94

82
31
11008567 • Rev AE • November 2009
Series 51 and 51-1 Motors
Service Manual
Adjustments
oveRview Adjust components of the Series 51 and Series 51-1 motors per following procedures
(where necessary, refer to
Pressure Measurement , pages 23-2 4 , for gauge port locations
and sizes):
Charge pressure relief valve
Set the charge pressure relief valve to the model order code specifications. In most
applications, the motor charge relief valve is set 2 to 4 bar [29 to 58 psi]
below the setting
of the pump charge relief valve (measured with the pump in its neutral or zero-angle
position). This setting assumes a reservoir temperature of 50° C [122° F]. Charge pressure
is referenced (additive) to case pressure.
measuring charge pressure
1. Install a 0 to 60 bar [0 to 1000 psi]
pressure gauge in port M1 or M2
(use which ever is at
low loop
pressure).
2. Install a 0 to 60 bar [0 to 1000 psi]
gauge in port L1 or L2 to measure
case pressure.
3. Operate the system with the prime
mover at normal operating speed
and the pump at half stroke (forward
or reverse).
Older Series 51 and Series 51-1 motors may be equipped with an external screw
adjustable charge pressure relief valve (not shown).

WARNING
This service procedure
may require disabling the
vehicle / machine (raising
the wheels off the ground,
disconnecting the work
function, and so forth)
while performing, in order
to prevent injury to the
technician and bystanders.
Take the necessary safety
precautions
Series 51 charge pressure relief valve
Adjustment
plug
1
1
/
16
lock nut
P101 208E
32
11008567 • Rev AE • November 2009
Series 51 and 51-1 Motors
Service Manual
Adjustments

WARNING
Incorrect charge pressure
settings may result in the
inability to build required
system pressure and / or
inadequate loop flushing
flows. You must maintain
the correct charge pressure
under all operation
conditions to maintain
pump performance
P101 209E
Series 51-1 charge pressure relief valve
1
1
/
16
inch
Adjustment plug
52 Nm [38 lbf•ft]
oveRview (continued) adjusting charge pressure
1. Loosen the lock nut using a 1 1 /
16
hex wrench.
2. Turn the adjustment plug with a large screwdriver or 13mm hex wrench.
Clockwise rotation of the plug increases the setting, and counterclockwise rotation
decreases the setting. The charge pressure setting will be reduced or increased at a rate
of approximately 3.4 bar [50 psi] per turn.
3. After adjusting the plug, torque the locknut to 52 N•m [38 lbf•ft]. Do not overtorque
4. Remove the gauges.
5. Reinstall the port plugs.
Motors with loop flushing defeated, or equipped with an orificed charge pressure relief
valve (see charge relief valve, orificed style on page 44) do not require adjustment.
32
11008567 • Rev AE • November 2009
Series 51 and 51-1 Motors
Service Manual
Adjustments

WARNING
Incorrect charge pressure
settings may result in the
inability to build required
system pressure and / or
inadequate loop flushing
flows. You must maintain
the correct charge pressure
under all operation
conditions to maintain
pump performance
P101 209E
Series 51-1 charge pressure relief valve
1
1
/
16
inch
Adjustment plug
52 Nm [38 lbf•ft]
oveRview (continued) adjusting charge pressure
1. Loosen the lock nut using a 1
1
/
16
hex wrench.
2. Turn the adjustment plug with a large screwdriver or 13mm hex wrench.
Clockwise rotation of the plug increases the setting, and counterclockwise rotation
decreases the setting. The charge pressure setting will be reduced or increased at a rate
of approximately 3.4 bar [50 psi] per turn.
3. After adjusting the plug, torque the locknut to 52 N•m [38 lbf•ft]. Do not overtorque
4. Remove the gauges.
5. Reinstall the port plugs.
Motors with loop flushing defeated, or equipped with an orificed charge pressure relief
valve (see charge relief valve, orificed style on page 44) do not require adjustment.