Loader Bobcat 853, 853H. Manual - part 21

SELECT VALVE (S/N 512811001 & Above) W/Select
Valve (JEM) (Cont’d)

Removal And Installation (Cont’d)

Remove the mounting bolts (Item 1) [A] located on the
outside left frame.

Remove the select valve.

Disassembly And Assembly

Clean the select valve to remove dirt before disassembly.

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

Remove the solenoid valve coils in Fig. [B].

NOTE: The controls wiring harness colors are listed

below for identification during select valve
assembly installation.

Second aux. male coupler (Item 1) [B] Yellow/Brown
Second aux. female coupler (Item 2) [B] Yellow/Lt. Green
High Flow (Item 3) [B] Lt. Blue/Red
Second aux. diverter (Item 4) [B] Yellow

Assembly: The coils largest opening (Item 1) [C] must
position on the valve shoulder (Item 2) [C]. Install the
washer (Item 1) [D] between the double coils. Install the
coils and tighten the nuts (Item 2) [D] to 5 ft.–lbs. (6,7 Nm)
torque.

A

P–09190

1

C

P–09177

2

1

D

P–09194

1

2

2

2

853, 853H BICS Loader

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Service Manual

B

P–09184

2

1

4

3

SELECT VALVE (S/N 512811001 & Above) W/Select
Valve (JEM) (Cont’d)

Disassembly And Assembly (Cont’d)

Remove the 4–way solenoid valve (Item 1) [A].

Remove the check valve (Item 2) [A].

Remove the pilot piston (Item 3) [A] located between the
check valves (Item 2) [A] & [B].

Remove the 2–way solenoid valves (Item 4) [A].

Inspect the solenoid valves for contamination or damage.
Wash all parts in clean solvent. Use air pressure to dry
them. Install new O–rings and back–up washers.

Remove the fitting (Item 1) [B]. Remove the check valve
(Item 2) [B].

Remove the relief valve (Item 3) [B].

Inspect the relief valve, check valves, pilot piston, and
fitting for contamination or damage. Wash all parts in
clean solvent. Use air pressure to dry them. Install new
O–rings and back–up washers.

The fitting (Item 1) [B] and fig. [C] has a poppet valve. The
poppet valve allows flow out of the select valve only.
Inspect the poppet (Item 1) [C] for smooth opening and
closing.

Assembly: Put oil on O–rings and back–up washers.
Install and tighten the solenoid valves (Items 1 & 4) [A] to
25 ft.–lbs. (33,9 Nm) torque. Install the pilot piston (Item
3) [A] in the port between the check valves (Item 2) [A]
& [B]. Install the check valves and tighten to 20 ft.–lbs.
(27,1 Nm) torque.

Install the fitting (Item 1) [B] and tighten to 20 ft.–lbs. (27
Nm) torque. Install the relief valve (Item 3) [B] and tighten
to 25 ft.–lbs. (33,9 Nm) torque.

Solenoid Testing

Use a test meter to measure coil resistance [D]. Coil wires
do not have polarity. Correct resistance for the coils is 5–8
ohms.

Replace the test meter with 12 volt power. You can see
and hear the spool shift.

A

P–09197

4

3

2

1

C

P–09195

1

D

P–09175

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853, 853H BICS Loader

Service Manual

B

P–09196

1

3

2

HYDRAULIC FILTER HOUSING

Removal And Installation

Disconnect the tubelines from the inlet of the hydraulic
filter [A].

Disconnect the hose (Item 1) [B] from the outlet of the
filter.

Remove the two mounting bolts and remove the hydraulic
filter and housing [C].

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

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

CD–10945

C

CD–10947

853, 853H BICS Loader

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Service Manual

B

CD–10946

1

B

P–10949

HYDRAULIC PUMP

Checking The Output Of The Pump

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

MEL10003 – Hydraulic Tester
MEL10006 – Hydraulic Test Kit

NOTE: Make sure all the air is removed from the

hydraulic system before beginning the test.

Air in the system can give an inaccurate test.

*Relief pressure must be per specification

before the test is done.

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

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

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

Disconnect the OUTLET hose from the pump [A].

Connect the INLET hose from the tester to the OUTLET
of the pump. Connect the OUTLET hose from the tester
to the hose which was disconnected from the pump [B].

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.

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 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
pressure 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)

% =

X 100

A low percentage may indicate a pump problem.

A

CD–11093

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853, 853H BICS Loader

Service Manual

853, 853H Service Manual #6720755 – Hydraulic System Section Part 1 of 2