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Stx-series — maintenance – Multiquip STX55J6 User Manual

Page 24

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PAGE 24 — STX-SERIES • RIDE-ON POWER TROWEL — OPERATION MANUAL — REV. #1 (07/16/04)

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Figure 25. Pressure Gauge (Hydraulic Pump)

Once the pressure gauges are installed and the spiders chained
together, the system can be checked.

With the foot pedal in the idle position and the engine at full
speed, the pressure should be 200 to 300 psi. If the pressure is
less than 200 psi, the charge system may need to be inspected
and/ or serviced. In particular, the suction filter and charge pump
relief valve should be checked. The suction filter may be plugged,
or the relief valve may be stuck. Either condition may cause low
charge pressure.

Checking Hydraulic Pressure

Many hydraulic problems are a result of low fluid levels. Before
checking any other possibilities, make sure the hydraulic fluid
level is up to the top of the sight glass which is located at the
back/center of the frame.

Hydrostatic pressure can be checked using a pressure gauge
with a range of at least 5,000 psi. Two male diagnostic quick
couplers (one for each pump) are located beneath the right grill
guard. To access couplers (Item B, Figure 26), remove the grill
guard. It is best to use two gauges simultaneously (Figure 25),
but it is possible to use only one gauge and repeat the procedure
for each side.

To fully test the hydrostatic system, the spiders will need to be
locked so that they cannot rotate. This can be done by wrapping
a chain around an arm on each spider, thus chaining them
together in the back of the trowel.

STX-SERIES — MAINTENANCE

With the engine at 50% to 70% of full speed, and spiders chained
together, slowly depress the foot pedal and read the gauges.
The pressure should get to at least 4,350 psi (300 bar). If the
pressure will not attain 4,350 psi (300 bar), the pump should be
inspected and/or serviced by an authorized service
representative.

LEFT SIDE PUMP

TEST PORT

PRESSURE GAUGE

5000 PSI RANGE

PRESSURE GAUGE

5000 PSI RANGE

3000

3000

5000

5000

bar

psi

bar

psi

4000

4000

200

200

250

250

300

300

50

50

100

100

150

150

1000

1000

2000

2000

WIKA

WIKA

RIGHT SIDE

HYDROSTATIC

PUMP

TEST PORT

USE A PARKER HANNIFIN

QUICK DISCONNECT

PD-SERIES DIAGNOSTIC

FEMALE COUPLER