Paccar CARCO 50B, Service Manual

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HYDRAULIC PUMP SERVICE
The hydraulic pump supplies oil to the control valve to
recharge the accumulator, apply clutches, release the
brake, and lubricate critical components. Maintaining
adequate oil flow is critical to reliable winch operation.
Pump flow should be tested with an accurate, commer-
cially available flow meter. If a flow meter is not available,
a serviceable flow meter may be fabricated from a gate
valve, tee and gauge as listed below.
•
Gate valve – ½ NPT port minimum, 1,000 psi (6,895
kPa) rating, minimum.
•
½ NPT schedule 80 pipe tee with a –8JIC hose adapter
on one run
•
Accurate 0-600 psi (0-4,137 kPa) gauge
Attach ½ NPT run end of tee to gate valve with –8JIC
adapter on opposite run.
Install gauge to branch of tee.
TEST PROCEDURE
1. Operate tractor and winch long enough to bring oil up
to operating temperature. Stop engine.
2. Remove access cover on right hand side of winch and
locate pump port on control valve labeled “P”. Remove
–8JIC pump line from the tee in the pump port of the
control valve.
3. Attach pump line to the gauge side of the gate valve or
flow meter. Direct the open end of the gate valve/flow
meter back into the winch case.
4. With gate valve/flow meter fully open, operate engine
at 650-700 RPM and measure oil flow by directing oil
into a container for 15 seconds.
5. Gradually close gate valve/flow meter until you have
applied 350 psi (2413 kPa) load to the pump. Again
record the flow for 15 seconds.
The minimum acceptable pump flow is 2 gpm (US) (7.6
lpm) at 650-700 RPM PTO speed and 350 psi (2413
kPa). Two quarts per 15 seconds equals 2 gpm.
If pump flow is below minimum:
1. Check/verify PTO speed and accuracy of tachometer.
2. Check suction strainer for restriction.
3. Check suction hose for cracks or poor connection.
4. Pump is worn and requires replacement.
HYDRAULIC PUMP REMOVAL
Remove the ½ in. capscrews which secure the bevel gear
inspection cover to the top of the winch case. Remove the
inspection plate. Remove the pump suction tube and
pressure hose from the pump. In most applications, the
pump may be removed from the bevel pinion carrier
through the top of the winch case. If this is not practical in
your application, then remove the bevel pinion carrier
from the winch case as described in the “Bevel Pinion
Carrier Service” section of this manual.
Remove the four capscrews and lockwashers (5, 6, 7)
securing the pump to the bevel pinion carrier.
Remove the pump assembly and wear plate (1) from the
bevel pinion carrier.
Thoroughly clean and inspect all pump components at
this time. If there is any sign of damage or wear which
may reduce pump performance, the entire pump assem-
bly must be replaced.
Do not fully close gate valve/flow meter as pump or
hose damage will result.
CAUTION
Preferred
Contact
Pattern
Central Toe Contact
Figure 1
Low Contact
High Contact
Pinion
Error
Pinion
Error
High Contact
Low Contact
Improper Contact
Patterns
Adjustment Req’d.
31