SANY SRT95C Off-Highway Truck. Service Manual

Installation

Note

: Tighten all the fasteners according

to section 38.2 'Technical Conditions for
Tightening Moment of Standard Bolts and
Nuts'.

Note

: Tighten all hydraulic pipelines with the

end face O-ring seal and replace all 'O'rings.

WARNING

Prevent personal injury and property loss

and ensure that the wheels are chocked

firmly. The chock and the hoist device

should have sufficient capacity. They

should be fixed firmly and can work safely.

1. The  spacer  (if  used)  should  be  placed
together with the balanced valve group on
the installation support and be fastened with
fasteners.
2. Connect the hose according to the sign
made during disassembly.
3.  Lift  up  the  body.  Check  the  hose  and
balanced valve group for leakage.
4. Connect pressure gauge with check point
'G'.  In  case  that  the  engine  reaches  the
maximum rotating speed, the second stage of
hoist cylinder is completed extended and the
leading pipeline is removed, check whether
the pressure of balanced valve is 17MPa (2465
psi).
5. Check the oil level according to chapter 15
'Hydraulic Oil Tank Assembly'. If the oil level

is relatively low, then refill oil. . The oil used

must conform to section 36.1 'LUBRICATION
AND MAINTENANCE'.

Maintenance

Regularly check the balanced valve group for
leakage and check the pressure according to
above 'installation' requirements.

Special tools

Hoist Pipeline And Joint

14.4 Power Supply of Pilot Valve

Group

Overview

The  Power  supply  of  pilot  valve  group  is
set on the support in the middle of the right
longitudinal  beam  and  on  the  hydraulic
pipeline between the steering pump and the
body hoist control handle. See Fig.2 for the
schematic diagram.
The leading supply valve is a pressure control
valve, which will reduce pressure for 21 Mpa (
3045 psi ) to 3.5 Mpa (500 psi) from steering
system  and  it  is  erected  with  accumulator
which pre-charged nitrogen pressure is 1.5
Mpa (217.5 psi ).

Maintenance

The pilot valve is a non-maintenance valve.
If it is damaged, it should be replaced as a
whole. The steps are shown as follow (See
Fig.1 for the number in brackets.):

Note

: Tighten all the fasteners according

to section 38.2 'Technical Conditions for
Tightening Moment of Standard Bolts and
Nuts'.

Note

: Replace all 'O'rings and tighten the

threads of all hydraulic pipelines.

WARNING

After the engine is shut down, the fluid

pressure will still remain in the system.

Operate the hoist control handle in the left

and right directions for about 15 times. Any

work can performed in the hoist control

system only after it is ensured the pressure

is discharged from the accumulator.

Otherwise, it may result in severe injuries

and deaths.

To prevent personal injury and property

damage, ensure that the wheels are

chocked properly and the hoist device has

sufficient capacity and can work safely.

Port “a” of

lifting valve

Port “b” of

lifting valve

Port “P” Brake valve

Fig.14.4-1 Assembly drawing of power supply
of pilot valve group

1. Power supply of pilot valve group
2. Screw

Fig.14.4-2 Schematic diagram of power supply
of pilot valve group

Hoist Pipeline And Joint

1. Park the truck in a horizontal working area,
ensure that the body is completely lowered
down, apply the parking brake and shut down
the engine.
2. Continuously operate the hoist lever valve,
release accumulator and chock all wheels
properly.
3. Make the signs on all of the hydraulic
pipelines connected to the power supply of
pilot valve group (1) to facilitate the installation.
Use a proper container to catch the leakage
oil. Remove the hydraulic pipeline and cover
all the ports of pipelines.
4. Remove the screw (2) and valve group (1)
from the mounting support.
5. Mark the positions of joints installed to the
valve, so that they can be used on the new
valve after they are removed from valve group
(1).
6. Install individual joints at the interfaces of
new pilot valve group (1).

7. Use the screw (2) to fix the pilot valve group

(1) onto the mounting support.
8. Remove the cover from the hydraulic
pipeline, and install the pipeline onto the valve
group (1) according to the signs made during
disassembly.
9. Check the oil level of the tank of hoist and
disc brake cooling system. If it is relatively low,

it will require filling of oil.

10. Remove the wheel chocks, start up the
engine .
11. Operate the valve control lever, check the
hydraulic pipeline joint for leakage and tighten
according to requirements.

Special tools

No requirement for specialized tools is
described in this section. These tools can be
purchased from the agent.

Hoist Pipeline And Joint

Hoist Pipeline And Joint

14.5 Hoisting Cylinder and

Installation

There are two hoisting cylinders between the
longitudinal beams of frame. The cylinder
through the bearing connected to the body.
The piston rod via the bearing too connected
to the frame. The hoisting cylinder is a two
acting cylinder, the power which drives the
body lower by the second acting of the
cylinder.

Removal

1. Park the truck in a horizontal area, raised
body, install the safety pin in the rear part of
truck, apply the parking brake, shut down the
engine and chock individual wheels.
2. Use a proper lifting device to bind the oil
cylinder firmly, and connect it to the lifting
equipment.
3. Place a clean container under the cylinder.
Set the hoisting lever moves on 'FLOAT'
position. Disconnect the hydraulic pipeline and
drain the oil. Makes the signs in the position
of individual oil interfaces, and block them to
prevent invasion of dirt.
4. Remove the screw, washer and upper pin
shaft from the cylinder.
5. Compress the cylinder and use the steel
wire to wrap it to prevent it from extending
during the removal.
6. Move the cylinder to a clean site for
disassembly.

Disassembly

1. Carefully disassemble for further inspects
the internal component of the cylinder.

Inspection

1. Use a proper solvent to completely clean
all parts and use dry soft linen to wipe
them. Carefully clean all grooves so that all
contaminants can be removed.
2. Use compressed air to blow and clean the

Fig.1 Hoisting Cylinder Outside Diagram

Hoist Pipeline And Joint

oil passage of individual cylinder tubes and
pistons to remove the contaminants.
3. Under good lighting condition, check
individual cylinder bodies for the presence of
the damages such as welding seam breakage
or obvious scratch and etc.
4. Use a hone to smoothen pushing burr, gap
and scratch. Replace all irreparable parts.
5. Check the threads of all screws and nuts for
damages. If necessary, replace them with new
parts.
6. Check whether all bushes and wearing rings
are excessively worn. If necessary, replace
them with new parts.
7. Replace all sealing elements, O-rings and
dust rings.

Assembly

1. Carefully assemble the oil cylinder. During
the assembly, be careful do not damage the
sealing elements.

warning

Prevent personal injury and property loss

and ensure that the wheels are chocked

firmly. The chock and the hoist device

should have sufficient capacity. They

should be fixed firmly and can work safely.

Installation

1. Wrap the cylinder with a proper lifting
device. Lift the cylinder onto the truck and
ensure that the lubricating oil port on the
piston rod support abutment of oil cylinder is
oriented to the in front part of truck.
2. Install the upper pins shaft on the piston rod
support abutment of oil cylinder at first, and

use the washer and screw for fixation.

3. Remove the plug. Connect the hydraulic
pipeline to the corresponding oil cylinder
interface according to the signs made during
disassembly.

Fig.1 Hydraulic oil tank assembly

1.Bolt

10.O-ring

2.Washer

11.Spacer flange

3.Cover Plate

12.Screw

4.O-ring

13.O-ring

5.Oil suction filter element

14.Breather valve

6.Plug

15.Screw

7.Oil suction filter element

16.Cover plate

8.Oil indicator

17.O-ring

9.Box body welding assembly

18.Oil return filter element

15 HYDRAULIC OIL TANK ASSEMBLY

15.1 Hydraulic Oil Tank Assembly

Hydraulic Oil Tank Assembly

3 4

Overview

The hydraulic oil tank assembly is shown in
Fig.1. The internal structure of hydraulic oil
tank assembly is shown in Fig.2.
The hydraulic oil tank assembly is composed
of cabinet welding assembly (9), oil suction

filter (5 , 6), oil return filter (18), breather valve

(14), oil sign (8), check valve (11), seal ring

and fastener, two flanged cover plates (3).

The oil tank is internally isolated by three
clapboards. Clapboard I divides the oil tank
into two parts as are shown in Fig.2; the left
side is steering and brake system oil tank and
the right side is the tank of hoist and cooling
system; clapboard II divides the oil suction
area and oil return area of tank of steering
and brake system; clapboard III divides the oil
suction area and oil return area of the tank of
hoist and cooling system.

Operating principle

The clapboard structure of hydraulic oil tank
is seen in Fig.2. The operating principle of
hydraulic oil tank is seen in Fig.3. The port
position of hydraulic oil tank is seen in Fig.4;
the digits in Fig.(1-4) are corresponding to
letters.
The hydraulic oil tank assembly is divided into
two parts by clapboard I in Fig.2 such as the
steering and brake system oil tank and the
hoist and cooling system oil tank.
The function of each port of the hydraulic oil
tank:
Port A: Connect the breather valve of the
hoist and cooling system tank
Port B: Connect the breather valve of the
steering and brake system tank
Port C: Connect the port T of the steering
valve group
Port D: Connect the prot T of the braking valve
group
Port E: Connect the prot T1 of the braking
valve group

Fig.2 Hydraulic oil tank partition structure

Fig.4 Diagram of hydraulic oil tank interface

Hydraulic Oil Tank Assembly

Partition

M L K

Port F: Connect the port T of the Leading oil
sources valve group
Port G: Connect the prot T of the foot-operated
valve
Port H: Connect the pressure switch
Port I: Connect the temperauture switch
Port J: Connect steering pump inlet
Port K: Connect steering pump outlet
Port L: Connect the cooling check valve
Port M:Connect cooling pump inlet
Port N: Connect cooling pump inlet
Port O: Connect hoist pump inlet
Port P: Connect cooling system confluence
block return opening
Port Q: Connect hoist pump outlet
Port S: Connect the oil sign of the steering
and brake system tank .
Port T: Connect the oil sign of the hoist and
cooling system tank
The oil in the steering and brake system is
pumped by the steering pump installed on

transmission PTO through oil suction filter (5)

port J; the oil is pumped into the steering valve
group of steering system and the brake valve
group of brake system. The internally leaked
oil of pump returns to the steering and brake
oil tank from the outlet of steering pump and
through port K. The returned oil of the steering
system returns to the steering and brake oil
tank from the steering valve group port T and
through port C indicated on Fig.3 and through

oil return filter (18).

The oil hoist system is pumped by the gear
pump installed to engine PTO through oil

suction filter (7) and port O; the oil is pumped

into the hoist valve of hoist system. If the
valve spool of hoist valve is located at the
hoist or forced landing position, the hydraulic
oil will enter the hoist system. The returned

oil will flow to the balanced valve group port T
through the hoist valve port T and then flow to

the tank of hoist and cooling system through
port Q indicated on Fig.3 and oil return filter
(18); when the hoist valve spool is located at

Fig.3 Functional diagram of hydraulic oil tank

Hydraulic Oil Tank Assembly

Steering and brake oil tank

Steering pump

Lifting pump

Lifting and cooling oil tank

Cooling pump

the neutral position, the hydraulic oil will enter
the confluence block and disc brake cooling
system; the other end of confluence block
is installed with a check valve with settling
pressure of 0.4MPa; when the cooling oil
pressure is higher than the settling pressure,
some oil will directly flow to the tank of hoist
and cooling system through the confluence
block, check valve 11 and port M indicated
on Fig.3. Oil return filter (18) are installed
with bypass valves, which will open when the
oil pressure increases to 3.4 bar due to the

blocking of filter. The oil will directly flow back

to the oil tank through check valve.
The pressure oil of disc brake cooling system
is pumped by the double-gear pump installed
to engine PTO through oil suction filter (7),
port M, N, and into the confluence block and
the disc brake cooling system; the returned oil

gathers at another confluence block and flows

to the hoist and cooling oil tank through port Q.
(14) indicates breathe valve respectively
installed to port A, port B of two oil tanks; (8)
indicates oil pointers respectively installed
to port P, port Q of two oil tanks; liquid level
sensors are respectively installed to port D,
port A of two oil tanks; when the liquid level
drops under a safe level, a signal will be sent
to light the alarm indicator on the instrument
panel. Meanwhile, the monitor will display
different fault codes; in addition, the two oil
tanks are installed with oil drainage cover (6)
respectively for maintenance.

The flange at port H of the steering and brake

oil tank is installed with an oil temperature
switch and an oil pressure switch; if the oil
temperature reaches 95°C or the oil pressure
reaches 0.17MPa, the alarm indicator on the
instrument panel in cab will light. Meanwhile,
the monitor will display different fault codes.

Check the oil level

Cold check

Unless otherwise specified, the number in

Hydraulic Oil Tank Assembly

bracket is detailed in Fig.1.
The tank of steering and brake system:
Stop the engine, turn the steering wheel left
and right, release the steering accumulator
pressure; continuously operate the foot
valve to release brake accumulator pressure
till the oil level reaches in the middle of oil
indicator(8). Refuel the tank of steering and
brake system as required with the hydraulic oil

specified in section 36.1 'LUBRICATION AND

MAINTENANCE' till the oil level reaches the
middle of oil indicator(8), and then mounts the
cover plate (5)back.
The tank of hoist and cooling system: Shut
down the engine, completely lower down the
body; the oil level should be kept in the middle
of oil indicator (8). Refuel the hoist and cooling
oil tank in accordance with the hydraulic oil

specified in section 36.1 'LUBRICATION AND

MAINTENANCE' till the oil level reaches the
middle of oil indicator (8), mounts the cover
plate (5)back.

Note

1. Park the truck at a flat area when checking

the oil level.
2. The normal oil level should be fully indicated
by  oil  indicator  (8)  if  the  oil  is  at  working
temperature.
In order to prevent the blowby between the
tank of steering and brake system and the
tank  of  cooling  system  which  results  the
leakage of oil from vent filter and hydraulic
pump  damage,  a  Ö10mm  through-hole  of
200mm away from the tank top is arranged
on clapboard I between two oil tanks.  The
blowby usually happens under the following
two conditions: 1) Hoist valve blowby: The
hoist  valve  cavity  oil  with  the  pressure  of
18MPa comes from tank of hoist and cooling
system; the hoist valve control cavity oil with
the pressure of 3MPa comes from the steering
and brake oil tank; When the valve spool is
working, the oil will leak from high pressure
cavity to low pressure cavity, that is, the oil

Hydraulic Oil Tank Assembly

blows by from the tank of  hoist and cooling
system  to  the  tank  of  steering  and  brake
system; such blowby is usually regarded as
rational leakage; 2) Brake blowby: The parking
brake oil comes from the stank of steering and
brake system with the pressure of 8.3MPa;
the travelling brake oil comes from the tank of
steering and brake system with the pressure
of 5.3MPa; the brake cooling oil comes from
the hoist and cooling oil tank with the pressure
smaller  than  0.4MPa;  if  the  brake  seal  is
damaged, the hydraulic oil will leak from high
pressure cavity to low pressure cavity, that is,
the oil blows by from the steering and brake oil
tank to the tank of hoist and cooling system; in
such case, the truck must be parked for repair.

Replacing the hydraulic oil

Unless otherwise specified, see Fig.1 for the
number in bracket
Tank body welding assembly (9) should be
emptied  and  cleaned  before  replacing  the
hydraulic  oil.  Refuel  clean  and  specified
hydraulic  oil  according  to  section  36.1
'LUBRICATION AND MAINTENANCE'.

Replacing the filter element

Unless otherwise specified, see Fig.1 for the
number in bracket.
Replace oil suction filter element (5), (13),
and oil return filter element (18) according
t o s e c t i o n 3 6 . 1 ' L U B R I C AT I O N A N D
MAINTENANCE'.

WARNING

To prevent personal injury and property

loss, ensure that wheel chocking material

is fixed properly and it has sufficient

capacity and works safely.

1. Place the truck in a flat working area,
ensure that the body is completely lowered

Hydraulic Oil Tank Assembly

down, apply the parking brake and shut down
the engine.
2. Rotate the steering wheel for several rounds
to  release  steering  accumulator  pressure;
continuously  press  the  foot  valve  down  to
release brake accumulator pressure; chock
the wheels, and set the accumulator main
switch to 'off' position.
3. Place a proper container, remove the end
cover from tank body welding assembly (4),
discharge the hydraulic oil, reinstall the end
cover and tighten again.
4. Remove bolt (1), washer (2) from tank body
welding assembly (9) and take down oil tank
cover plate(3).
5.  Remove  and  discard  oil  suction  filter

element (5), (7) and oil return filter element (18)

from tank body welding assembly (9).
6. Install new oil suction filter element (5),
(7)and oil return filter element (18) to tank
body welding assembly (5) and tighten with a
special tool.
7. Replace O-ring (4), install cover plate (3),
bolt (1), washer (2) again onto tank body
welding assembly (9) and tighten bolts with a
torque spanner.
8. Refuel the oil tank to correct liquid level
according to section 36.1'LUBRICATION AND
MAINTENANCE', then mounts the breath
valve.

9. Remove wheel chocks, start the engine, fill

the system pipeline and check the liquid level
according to 'Oil Level Inspection'.

Oil tank assembly

Disassembly

Unless otherwise specified, see Fig.1 for the
number in bracket.

WARNING

In order to prevent personal casualty and

equipment damage, make sure the wheels

Hydraulic Oil Tank Assembly

are securely chocked and the hoist device

is capable of working safely.

1. Place the truck in a horizontal working area,
ensure that the body is completely lowered
down, apply the parking brake and shut down
the engine.
2. Chock all the wheels.
3. Remove two end covers (6) from the
hydraulic oil tank assembly, discharge the
hydraulic oil into a proper container, reinstall
the end cover and tighten it.
4. Mark all the pipelines connected to the oil
tank, use a proper container to collect the
leaked oil, remove all the steep pipes and
rubber hoses connected to the oil tank, and
cover up the pipe ends with covers or end
covers.
5. Lift the oil tank assembly with a proper hoist
device.
6. Remove the bolts, nuts and washers on
the two sides of oil tank assembly used for
fastening.
7. Move the hydraulic oil tank assembly to a
proper site for disassembly.

Disassembly

Unless otherwise specified, see Fig.1 for the
number in bracket.
Remove all the parts from the hydraulic oil
tank assembly.

WARNING

The oil tank is heavy. In order to prevent

personal injury and equipment damage,

make sure the hoist device has sufficient

bearing capacity and is fastened correctly.

Inspection

Unless otherwise specified, see Fig.1 for the
number in bracket.

Hydraulic Oil Tank Assembly

WARNING

Please wear appropriate protective cover

when blowing the oil tank and part with

compressed air, in order to prevent liquid

splashing.

1. Clean the hydraulic oil tank assembly and
its parts with kerosene and blow dry with
compressed air.
2. Check the oil tank welding seam and
internal welding pieces for crack and leakage.

3. Check oil suction filter element (5), (7) and
oil return filter element (18) for damage, and if

necessary, replace with new parts.
4. Check breath valve (14) for damage, and if
necessary, replace with a new one.
5. Check 'O'ring (4) for damage, and if
necessary, replace with a new one.

Assembly

Unless otherwise specified, see Fig.1 for the
number in bracket.
Install all the parts of the hydraulic oil tank
assembly indicated on diagram.

Installation

Unless otherwise specified, see Fig.1 for the
number in bracket.

Note

: Tighten all the hydraulic pipelines with

O-ring end seal.

WARNING

In order to prevent personal injury and

equipment damage, make sure the wheels

are chocked, the chocking materials

and hoist device have sufficient bearing

capacity and are connected reliably.

1. Lift the hydraulic oil tank assembly to

Hydraulic Oil Tank Assembly

SANY SRT95C Off-Highway Truck. Service Manual - page 22