Loader Bobcat 773. Manual - part 33

C

P–04351

1

2

HYDRAULIC PUMP (Cont’d)

Checking The Output Of The Hydraulic Pump

The tools listed will be needed to do the following
procedure:

MEL 1429 – Remote Start Switch
MEL10003 – Hydraulic Tester
MEL10006 – Hydraulic Test Kit

NOTE: *Relief pressure must be per specification

before the test is done.

Disconnect the OUTLET hose (Item 1) [A] from the
pump.

Connect the INLET hose (Item 1) [B] from the tester to the
OUTLET fitting (Item 1) [C] of the pump. Connect the
OUTLET hose (Item 2) [B] from the tester to the hose
(Item 2) [C] which was disconnected from the pump.

W–2017–0286

Put jackstands under the front axles and rear
corners of the frame before running the engine
for service. Failure to use jackstands can allow
the machine to fall or move and cause injury or
death.

The hydraulic tester must be in the fully open
position before you start the engine.

I–2024–0284

Lift and block the loader. (See Page 1–1.)

Raise the lift arms and install an approved lift arm support
device. (See Page 1–1.)

Rasie the operator cab. (See Page 1–1.)

Connect the remote start switch. (See Page 1–1.)

NOTE: Photos may appear different but the

procedure is the same.

Revised Jan. 99

Never work on a machine with the lift arms up
unless the lift arms are secured by an approved
lift arm support device. Failure to use an
approved lift arm support device can allow the
lift arms or attachment to fall and cause injury
or death.

W–2059–0598

A

N–15482

1

B

N–15776

2

1

–2–78–

773 BICS Loader

Service Manual

HYDRAULIC PUMP (Cont’d)

Check The Output Of The Hydraulic Pump (Cont’d)

Sample tester connection shown [A].

Start the engine and run at low idle RPM. Make sure the
tester is connected correctly. If no flow is indicated on the
tester, the hoses are connected wrong. With the hoses
connected correctly, increase the engine speed to full
RPM*.

Warm the fluid to 140

°

F. (60

°

C.) by turning the restrictor

control (Item 1) [A] on the tester to about 1000 PSI (6895
kPa). DO NOT exceed system relief pressure. Open the
restrictor control and record the free flow (GPM) at full
RPM.

Push the mode switch (on the remote start switch) to
engage the front auxiliary hydraulics, the light will come
ON. Push the button (on the right steering lever) for fluid
flow to the quick coupler (fluid pressure will go over main
relief). Record the highest pressure (PSI) and flow
(GPM). The high pressure flow must be at least 80% of
free flow.

HIGH PRESSURE FLOW (GPM)

FREE FLOW (GPM)

A low percentage may indicate a failed pump.

*Refer to SPECIFICATIONS Section 9–1 for system
relief pressure and full RPM.

% =

X 100

A

BH–00196

Hydraulic Control

Valve

Reservoir

Hydraulic Pump

In

Out

1

EXAMPLE: TESTER

CONNECTION

773 BICS Loader

–2–79–

Service Manual

HYDRAULIC PUMP (Cont’d)

Disassembly And Assembly

Mark the pump sections for correct assembly.

Loosen the pump bolts [A].

Assemble: Tighten the bolts to 25 ft.–lbs. (34 Nm)
torque.

Remove the pump housing bolts [B].

Remove the end housing [C].

Remove the O–rings and seals from the end housing [D].

When repairing hydrostatic and hydraulic
systems, clean the work area before
disassembly and keep all parts clean. Always
use caps and plugs on hoses, tubelines and
ports to keep dirt out. Dirt can quickly damage
the system.

I–2003–0888

A

CD–10735

C

CD–10737

D

CD–10738

–2–80–

773 BICS Loader

Service Manual

B

CD–10736

HYDRAULIC PUMP (Cont’d)

Disassembly And Assembly (Cont’d)

Remove the mounting flange end housing [A].

Remove the O–ring and seal from the end housing.

Remove the bearing housing [B].

Remove the drive gear [C].

Remove the idler gear [D].

A

CD–10739

C

CD–10741

D

CD–10742

773 BICS Loader

–2–81–

Service Manual

B

CD–10740