Loader Bobcat 773. Manual - part 38

HYDROSTATIC SYSTEM INFORMATION

Replenishing Valve Function

The functions of the replenishing valves are:

1. To give replacement fluid to the low pressure side

of the hydrostatic circuit. Replacement fluid is
needed because of normal internal leakage and
the controlled flow to the oil cooler for cooling;
Function 1 [A].

2. To keep high pressure fluid out of the low pressure

side of the hydrostatic circuitry; Function 2 [A].

Checking Charge Pressure

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

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.

W–2017–0286

Open the rear door.

Disconnect the wires (Item 1) [B] from the charge
pressure sender.

Remove the charge pressure sender (Item 2) [B] from
fitting.

Install a gauge (Item 1) [C] as shown.

Start the engine.

The gauge must read as follows:

200 PSI (1379 kPa) with approximately 120

°

 F (49

°

 C)

fluid.

If the charge pressure is not correct remove the charge
relief valve at the pump. (See Page 3–40.)

Check the poppet and spring for wear or damage.

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

B–02804

CHARGE OIL

Valve Moves for Charge

Oil Replacement

Valve Stays on Seat to

Hold High Pressure for Drive

FUNCTION 1

FUNCTION 2

B

N–00973

1

2

C

N–00973

1

–3–4–

773 BICS Loader

Service Manual

CONTROL PANEL

Removal and Installation

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

Remove the engine speed control. (See Page 7–1.)

NOTE: If the loader is equipped with rear auxiliary

hydraulics, also disconnect the electrical
connectors from the left side steering lever.

Scribe a mark across the top of the steering linkage bars
(Item 1) [B] which are connected to the steering shaft on
the control panel.

Remove the four steering linkage mounting bolts (Item 2)
[B].

Installation:  Align the marks on the steering linkage
bars. Tighten the steering linkage mounting bolts to
25–28 ft.–lbs. (34–38 Nm) torque.

Remove the four control panel mounting bolts (Item 1) [C]
from both sides of the control panel.

Installation: Tighten the control panel mounting bolts to
25–28 ft.–lbs. (34–38 Nm) torque.

Remove the control panel from the loader.

Reverse the removal procedure to install the control
panel.

Loosen the jam nut (Item 1) [A] from the by–pass control
knob (Item 2) [A].

Remove the control knob (Item 2), jam nut (Item 1) and
rubber washer (Item 3) [A].

Disconnect the control harness connectors (Item 4) [A]
from the right side steering lever.

NOTE: Photo’s may appear different but the

procedure is the same.

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

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

1

3

2

4

P–04188

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.

W–2017–0286

C

P–04073

1

1

773 BICS Loader

–3–5–

Service Manual

B

P–04074

2

1

1

2

NOTE: The steering shaft can be removed without

removing the control panel from the loader.
Photo [B] shows the control panel removed
for clarity purpose only.

Remove the steering linkage mounting bolts (Item 3) [A].

Remove the steering shock mounting nuts (Item 2) [A].

Remove the steering shaft pivot bolt (Item 1) [B] from
both sides of the control panel.

Installation:  Tighten the pivot bolts to 180–200 in.–lbs.
(21–23 Nm) torque.

Remove the steering shaft from the control panel.

Steering Shaft Disassembly And Assembly

Disassemble the right and left steering shafts from the
cross shaft assembly [C].

Assembly:  Install new nylon bushings (Item 1) [C] as
needed when assembling the steering shaft. Be sure to
apply grease on the cross shaft before installing the right
and left steering shaft.

To remove the steering shaft mounting bracket (Item 2)
[B], remove the three mounting bolts (Item 1) [D] from the
front of the control panel.

Remove the steering shaft mounting bracket.

Installation: Tighten the mounting bolts to 25–28 ft.–lbs.
(34–38 Nm) torque.

CONTROL PANEL (Cont’d)

Steering Shock Removal And Installation

Remove the mounting nut (Item 1) [A] from the end of the
shock connected to the steering linkage.

Remove the mounting nut (Item 2) [A] from the other end
of the shock connected to the bracket on the control
panel.

Installation: Tighten the mounting bolts to 25–28 ft.–lbs.
(34–38 Nm) torque.

Steering Shaft Removal And Installation

NOTE: Photo’s may appear different but the

procedure is the same.

A

P–04069

3

2

1

C

P–04154

1

1

1

D

P–04193

1

1

–3–6–

773 BICS Loader

Service Manual

B

P–04146

1

2

CONTROL PANEL (Cont’d)

Steering Lever Removal And Installation

Disconnect the electrical connectors from the steering
lever [A].

NOTE: Photo’s may appear different but the

procedure is the same.

Remove the nuts from the two U–bolts (Item 1) [A] used
to mount the steering lever.

Remove the U–bolts from the steering lever mount.

Remove the steering lever (Item 2) [A] by sliding the lever
through the rubber boot (Item 1) [B] on the front of the
control panel.

Installation: Tighten the u–bolts so the lever can not be
moved either right or left when seated in the operator
seat. Be sure the steering lever does not interfere with the
operator cab when lowering or raising the cab.

Rubber Boot Replacement

To replace the rubber boot (Item 1) [B] on the control
panel, remove the steering lever (See above procedure).

Drill out the four rivets (Item 2) [B] located on the flange
of the rubber boot and remove the old boot.

Install the new boot and reinstall the steering lever.

A

P–04188

2

1

773 BICS Loader

–3–7–

Service Manual

B

P–04193

2

1

3