Section E - Hydraulics

Pumps
Start-up Procedure

Start-up Procedure

A168042-B2
Fig 49.

The following start-up procedure should always be

followed when starting up a new installation or when
WARNING
restarting an installation in which either a pump or motor Fluid Under Pressure
has been removed from the system. Fine jets of fluid at high pressure can penetrate the
skin. Keep face and hands well clear of fluid under
Note: If a new or rebuilt pump is being fitted always refill pressure and wear protective glasses and gloves.
the pump with filtered oil prior to start up via a 10 micron Hold a piece of cardboard close to suspected leaks
filter (no by-pass).. Use the correct oil. See Fluids, and then inspect the cardboard for signs of fluid. If
Lubricants and Capacities, Section 3. fluid penetrates your skin, get medical help
immediately.
WARNING INT-3-1-10_3

This procedure requires the machine to be disabled Place the machine safely onto blocks, so that all four
(wheels raised off the ground, work function wheels are clear of the ground. Ensure that the machine is
disconnected, etc.) while the procedure is carried out. stable.
HYD-8-1_2
Check that the pump inlet line from the hydraulic filter to
the pump unit is filled with fluid, by 'cracking' the hose
WARNING connection at the rear main pump.
Hydraulic Pressure
Hydraulic fluid at system pressure can injure you. Install a 0 - 35 bar (0 - 500 lb/in2, 0 - 35 kgf/cm2) pressure
Before disconnecting or connecting hydraulic hoses gauge in the charge pressure gauge port A, to monitor the
or couplings, vent the pressure trapped in the hoses in charge pressure. After machine serial no. 751012 a test
accordance with the instructions given in this point is provided which, up to serial no. 751715, is
publication. positioned under the pump as shown at B.
HYD-1-5 Fig 50. ( E-76) From serial no. 751716 this test point

E-75 9803/9960-1 E-75

 Section E - Hydraulics
Pumps
Start-up Procedure
is positioned at the rear of the left hand side of the engine whilst slowly increasing the throttle lever setting until the
as shown at C. Fig 51. ( E-76) engine starts and runs atthe lowest possible speed.

As air leaves the system, the charge pressure (as

indicated on the gauge) should rise to a minimum of 7 bar
(7 kgf/cm2 100 lb/in2).If the charge pressure is incorrect,
shut-down and determine the cause.

Once the correct charge pressure has been established,

operate the drive system 10 times in all directions with the
engine at idle then slowly increase the engine speed whilst
continuing to operate the system. Finally operate the
system in all directions several times with the engine
running at maximum speed.

Shut down engine and remove the pressure gauge. Check

the system fluid level and top up as necessary.

S246240-B1
Fig 50.

348890-B2
Fig 51.

Remove the ESOS fuse to prevent the engine from

starting. With the Drive Control Lever (in the cab) at
Neutral, 'jog' the engine using the starter. The pressure
gauge should show a small rise in pressure as the engine
turns. If so, replace theESOS fuse and operate the starter

E-76 9803/9960-1 E-76

 Section E - Hydraulics
Pumps
Hydrostatic Pump from machine no. 751012

Hydrostatic Pump from machine no. 751012

Dismantling and Assembly 8 Install new O-ring 5 onto seal carrier 3 and lubricate
with petroleum jelly.
Note: Following a complete rebuild of this pump it is
necessary for it to be set up on a dynamic test jig. Because 9 Wrap the splined end of shaft 2 with thin plastic to
of this it is recommended that no dismantling work is prevent damage to the lip seal during installation.
carried out beyond that covered in this manual.
10 Slide seal carrier 3 over shaft 2 and press into
position in the pump body recess.

11 Holding inward pressure against shaft 2, refit circlip 1

Removal and Replacement to secure the assembly.

1 Remove circlip 1.

Note: It may be necessary to press shaft 2 into the body

against spring force before the circlip can be removed.
When the circlip is removed, seal carrier 3 will move out
approximately 6 mm (0.25 in.) due to spring force.

2 Lightly tap the end of shaft 2 with a rubber mallet and

remove seal carrier 3.

Note: After the seal carrier has been removed, the shaft 2
and bearing assembly 4 are free in the body. Under no
circumstances should the shaft be removed as this could
cause loss of alignment of the pump internals
necessitating a total strip and rebuild. Such a procedure is
outside the scope of this Service Manual.

3 Remove O-ring 5 from seal carrier 3. Discard the O-

ring.

4 Using a suitable press, press out lip seal 6 from the

seal carrier. Discard the lip seal.

5 Inspect seal carrier 3 for damage, and the sealing

area on shaft 2 for signs of rust, wear or
contamination. Polish the sealing area on the shaft if
necessary.
S244910-B1
6 Coat the outside diameter of new lip seal 6 with Fig 52.
suitablesealant. Press the lip seal into the shaft
bearing side of seal carrier 3, ensuring that the seal
lip faces the shaft bearing. Take care not to damage
the lip seal.

7 Lubricate the inside diameter of lip seal 6 with

petroleum jelly.

E-77 9803/9960-1 E-77

 Section E - Hydraulics
Pumps
Hydrostatic Pump from machine no. 751012

Charge Check and High Pressure Relief

Valves
Dismantling and Assembly

The charge check and high pressure relief valves are

identical. The procedure for dismantling and assembly is
therefore the same for both valves.

1 Unscrew plug 1 from the pump body.

2 Remove the relief valve assembly 2 from the body.

The smaller end of the conical spring is crimped to
retain it on the relief valve.

Note: The High Pressure Relief Valve is factory set and

cannot be repaired.

3 Remove and discard O-rings 3 and 4, and back-up

ring 5 from plug 1.

4 Inspect relief valve 2 and mating seat in plug 1 for

damage. Replace if necessary.

5 Install a new outer O-ring 3, new back-up ring 5 and

new inner O-ring 4 on plug 1.
S244930-B1

6 Check that the conical spring is correctly retained on Fig 53.

relief valve and install the valve in the pump body.

Note: The conical spring must be correctly retained on the

relief valve to ensure satisfactory pump operation.

7 Refit plug 1 and torque tighten to 68 Nm (50 lbf ft).

E-78 9803/9960-1 E-78

 Section E - Hydraulics
Pumps
Hydrostatic Pump from machine no. 751012

Charge/Anti-stall Valve
Dismantling and Assembly

1 Mark the plug 1, locknut 2 and the pump body so as

to maintain approximately the original adjustment.

2 Loosen locknut 2 and unscrew plug 1 from pump

body. Remove O-ring 3 from plug 1 and discard O-
ring.

3 Remove spring 4 and poppet 5 from pump body.

4 Inspect poppet 5 and mating seat in pump body for

damage. Renew as necessary.

5 Install a new O-ring 3 on plug 1.

6 Fit poppet 5 and spring 4 into pump body.

7 Screw plug 1 complete with locknut 2 into pump body

to align with the marks made during disassembly.
Tighten the locknut.

8 Check the charge pressure and adjust as

necessary. Charge Pressure Checking and
Adjustment ( E-70)
S244920-B1
Fig 54.

E-79 9803/9960-1 E-79

 Section E - Hydraulics
Pumps
Hydrostatic Pump from machine no. 751012
Position the operator s seat facing forwards so that the
brakes are released.
This procedure may be carried out if the machine creeps
when the drive joystick is in the neutral position. This fault 1 Identify which pump section requires adjustment.
may be due to an incorrect neutral setting of the servo
piston. Before attempting any adjustment, carry out the If the machine veers to the left this could be caused
following preliminary checks. by either the right hand wheels moving forward or the
left hand wheels moving in reverse. Remember that
1 Check tyre pressures and condition. pump P1 drives the left hand motor and pump P2
drives the right hand motor.
The pressure of one tyre may be low or one or both
tyres on one side of the machine may be new and the
other tyres worn. In both these cases the rolling
circumference of the tyres will be unequal causing the
machine to veer to one side.

2 Check chain tension.

Chains which are tensioned unequally will cause the

machine to veer to one side. Always adjust the
tension on all four chains, never just one.

3 Check brake release pressure, seal failure.

Low pressure or faulty seals may cause the brake to

drag on one side. Check the pressure at theanti-stall
valve. Check the seal by using a hand pump to
release the brake and see if the pressure holds.

4 Check the drive joystick

Check that the joystick spools are not sticking and are
correctly operated by the lever.

Note: If the fault cannot be rectified by any of the above S244940-B1

Fig 55.
checks or adjustment, then either the pump or motor could
be faulty. To identify which, swop the motor feed hoses at
2 Stop the engine.
the pump. If the machine now veers in the opposite
direction then the pump is faulty. If the machine continues
3 Remove the floor plates.
to veer in the same direction the the motor is faulty.
4 Loosen locknut A and turn the neutral adjusting
Adjustment procedure
screw B 1/10 of a turn in the required direction then
re-tighten the locknut.
WARNING
If the wheels are creeping forward, turn the adjusting
This procedure requires the machine to be disabled screw in a clockwise direction (looking underneath
(wheels raised off the ground, work function the pump). If the wheels are creeping in reverse, turn
disconnected, etc.) while the procedure is carried out. the screw anti-clockwise.
HYD-8-1_2

Note: This adjustment is very sensitive. Turn the adjusting

Place the machine safely onto blocks, so that all four
screw 1/10 of a turn at a time and re-check. A slight
wheels are clear of the ground. Ensure that the machine is
movement when the wheels are raised is acceptable
stable.

E-80 9803/9960-1 E-80

 Section E - Hydraulics
Pumps
Hydrostatic Pump from machine no. 751012
provided that no movement occurs when the machine is
resting on the ground.

5 Start the engine and check that the wheels are

stationary.

6 Finally tighten locknut A to 23 Nm (17 lbf ft), taking

care to retain the set position of adjusting screw B.

7 Re-check for wheel movement.

E-81 9803/9960-1 E-81

 Section E - Hydraulics
Pumps
Auxiliary Pump (Standard machines)

Auxiliary Pump (Standard machines)

S167751-V1
Fig 56.

Removal and Replacement Dismantling

Remove bolts X and lift the pump away from the main Remove coupling A if still fitted.
pump unit.
Hold the body in a soft jawed vice with the mounting flange
On replacement, torque tighten the bolts to 77 Nm (57 lbf uppermost. Mark all parts to ensure correct alignment
ft, 7.9 kgf m). when assembling. Discard all seals and sealing rings.

Dismantling and Assembly Clean all parts in light aromatic kerosene, examine for
damage and wear.
The numerical sequence shown on the illustration is
Damaged or worn parts must be renewed.
intended as a guide to dismantling. Fig 56. ( E-82)

For assembly the sequence should be reversed. Inspection

It is normal for the gears to have cut a slight track in the

body bore on the inlet side. The gear track wear can not be

E-82 9803/9960-1 E-82

 Section E - Hydraulics
Pumps
Auxiliary Pump (Standard machines)
measured accurately but will be related to bearing wear. Fit the cover 8, ensuring the inlet side is in the
Examine the bearing bores C which are coated during correctposition. Torque tighten bolts 1 to 61 - 68 Nm (45 -
manufacture with PTFE. If the grey PTFE is worn through 50 lbf ft, 6.2 - 7.0 kgf m).
so that the bronze base is visible, the complete pump must
be renewed. Fig 57. ( E-83) If the inlet adapter is disturbed, fit a new O ring and tighten
to 115 - 145 Nm (85 - 107 lbf ft, 11.7 - 14.8 kgf m). Do not
overtighten.

If the outlet adapter is disturbed, clean the threads and

apply JCB Threadlocker and Sealer to two of the threads.
Tighten to 95 Nm (70 lbf ft, 9.7 kgf m). Do not overtighten.

When refitting the auxiliary pump to the Hydrostatic pump,

tighten mounting bolts to 77 Nm (57 lbf ft, 7.9 kgf m).

Testing

Install the pump onto a suitable test rig and test as follows.
Table 17. Test Data ( E-83)

Table 17. Test Data

deg deg
Oil 45 - 50 deg C (113 - 122 deg F) at pump
139690-V1
Temperature inlet
Fig 57.

Renew the pump if the bearings are scored or if the gear

side faces are chipped or damaged. DO NOT use Run pump initially off load and check for leaks. Increase
anyabrasives on the bearings or gears as this would pressure in stages of 40 bar (600 lb/in2, 40 kg/cm2) and
destroy critical manufacturing dimensions. allow to run for 1 minute at each stage. This will allow
components to readjust and flow readings will indicate if
Assembly rebuild is correct. Check pump output under the following
conditions. Table 18. ( E-83)
Fit the pressure loading ring/backing ring 10 and sealing
rings 11 to the flange 2 and cover 8. A little grease (JCB Table 18.
MPL Grease) in the grooves will help retain them. 2 2

Hold the flange 2 in a soft jawed vice with the sealing rings
facing upwards and assemble the body 3. Ensure that the
body cut-in track corresponds to the inlet side of the flange.

Assemble the gear/bearing pack components 4, 5, 6 and 7

separately. It is important to return the flange end bearing
6 to the flange end of the unit, otherwise internal leakage
can occur due to bedding in. Ensure that the bearing face
recesses B are adjacent to the gear faces and that the
relieved radii are both towards the pump outlet.

Lightly lubricate the body bore and bearings, then push the
gear/bearing pack into the body.

E-83 9803/9960-1 E-83

 Section E - Hydraulics
Pumps
Auxiliary Pump (High-flow machines)

Auxiliary Pump (High-flow machines)

Dismantling and Assembly Lightly lubricate threads of bolts 1 and finger tighten only.

Note: Before removing and dismantling the pump, check Hold flange 2 in a vice and apply a force of 200-250 N (45-
flow and pressure. If either of these is low, renewal of 55 lbf) to body 3 at position indicated by arrow X (within 10
components such as gears, bearings and housings will not mm [0.4 in] of the flange). Whilst maintaining this force,
effect a permanent cure. If the pump output is satisfactory torque tighten bolts 1 in a diagonal sequence. This
but there is external leakage, the pump may be removed procedure is necessary to ensure metal to metal contact
and dismantled for re-sealing only. between front bearing lobes and inlet side of body.

The numerical sequence shown on the illustration is Torque tighten bolts 1 to 61 - 68 Nm (45 - 50 lbf ft, 6.2 - 7.0
intended as a guide to dismantling. Fig 58. ( E-85) kgf m).

For assembly the sequence should be reversed. If the inlet adapters are disturbed, fit new O rings and
tighten to 115 - 145 Nm (85 - 107 lbf ft, 11.7 - 14.8 kgf m).
Do not overtighten.

If the outlet adapters are disturbed, clean the threads and

Mark housings and covers to ensure correct re-assembly. apply JCB Threadlocker and Sealer to two of the threads.
Keep bearing blocks 6, 8, 16, 18 and gears 4, 5, 14 and 15 Tighten to 95 Nm (70 lbf ft, 9.7 kgf m). Do not overtighten.
together in sets to ensure refitting of the bearing blocks in
their original positions.

Extended bush A in bearing block 6 is a light push fit in

flange 2.

DO NOT remove plug B as it is an interference fit,

assembled to a critical dimension.

Inspection

Wash all components then apply hydraulic oil immediately

afterwards to prevent moisture from collecting.

It is normal for the gears to have cut a slight track in the

body bore on the inlet side. The gear track wear cannot be
measured accurately but will be related to bearing wear.
Examine the bores of the bearing blocks 6, 8, 16 and 18
which are coated during manufacture with PTFE. If the
grey PTFE is worn through so that the bronze base is
visible, the complete pump must be renewed.

Renew pump if faces of bearing blocks are scored or if side

faces of gears are chipped or damaged. DO NOT use any
abrasives on the bearing blocks or gears as this would
destroy critical manufacturing dimensions.

When Assembling

Renew all seals. Hold them in position with grease during

assembly. Ensure that the ends of seals 7, 9, 17 and 19 do

not overhang the bearing blocks to become trapped in the
housings.

Bearings must be assembled with cast recesses (not seal

grooves) against gear faces and with seal ends towards
theinlet side of the pump.

E-84 9803/9960-1 E-84

 Section E - Hydraulics
Pumps
Auxiliary Pump (High-flow machines)

291090-V1
Fig 58.

E-85 9803/9960-1 E-85

 Section E - Hydraulics

Valves
Loader Valve

205110-B2
Fig 59.

Removal WARNING
Remove rear floor plates. See Floorplates, Section 3. Hydraulic Pressure
Hydraulic fluid at system pressure can injure you.
Before disconnecting or connecting hydraulic hoses
or couplings, vent the pressure trapped in the hoses in
accordance with the instructions given in this
publication.
HYD-1-5

Before working on the hydraulic system ensure that the

engine is switched off and the starter key removed.

E-86 9803/9960-1 E-86

 Section E - Hydraulics
Valves
Loader Valve
Vent the hydraulic pressure. Venting Hydraulic
Pressure ( E-7) Drain the hydraulic tank.

Disconnect all hydraulic hoses from the valve ports (one

check valve at inlet A, six work ports B, four servo
connections C (two on the opposite side), one high
pressure carry over D and one outlet E). Cover exposed
connections to prevent ingress of dirt. Mark the hoses to
ensure correct reconnection.

Disconnect the electrical connectors to the solenoids.

Mark

the connectors to ensure correct reconnection.

Remove the securing nuts from mounting lugs F and lift the
valve block from the machine.

Replacement
Replacement is a reversal of the removal procedure.

Ensure all hoses and ports are clean and free from dirt.
securing nuts to 56 Nm (5.7 kg fm, 42 lbf ft)

E-87 9803/9960-1 E-87

 Section E - Hydraulics
Valves
Loader Valve

Dismantling and Assembly Ensure that the spools are inserted with their larger
waisted sections towards the bottom.
Fig 60. ( E-89)
Lubricate all parts with hydraulic oil before assembly and
Dismantling all 'O' rings and seals with vaseline.

Always work on a clean, dirt free surface. Torque Settings

1 Remove the plug from port B. Item Nm kgf m lbf ft

Tie Rod 10 (1 off) 44.75 4.6 33.0
2 Remove the cap screws 1 from the end caps 2.
Carefully remove the 'O' ring 3, spring seat 4 and Tie Rod 13 (2 off) 20.0 2.0 14
spring 5 from each end cap 2. Keep all parts of each A.R.V. 18 (3 off) 44.75 4.6 33.0
end cap together. Discard 'O' ring 3.
M.R.V. 22 (1 off) 44.75 4.6 33.0
Note: The four end caps 2 are identical. Do not mixparts Plug 20 (3 off) 44.75 4.6 33.0
between individual end caps. Plug B (1 off) 9.5 1.0 7.0

3 Remove cap screws 6 from the solenoids 7, then Cap screws 1

remove the solenoids (2 off). &6

4 Remove nuts 8 (2 off) and washers 9 (2 off) from tie

rod 10, withdraw tie rod 10.

5 Remove nuts 11 (4 off) and washer 12 (4 off) from tie

rods 13 (2 off), withdraw tie rods 13.

6 Carefully separate inlet section C, operation sections

E, F, G and outlet section D. Discard the 'O' rings 14
(4 off) from between the sections.

Note: Work on the operation sections E, F, G individually.

Do not interchange parts from individual sections.

7 Carefully push out the check valve 15 and spring 16.

Push out the spool 17. (Only spool E is described, but
F and G are similar.)

8 Remove the auxiliary relief valves 18 (2 from E, 1

from F).

9 Remove plugs 20 (1 from F, 2 from G), remove and

discard 'O' rings 21 (3 off).

10 Remove the main relief valve 22 from the inlet section

C. Remove and discard 'O' ring 23.

11 Remove the test connector 24 from the inlet section.

Remove and discard 'O' ring 25.

12 Clean all parts in kerosene, inspect and check for

damage.

Damaged sections should be replaced complete.

Assembly

Renew all seals and 'O' rings.

E-88 9803/9960-1 E-88

 Section E - Hydraulics
Valves
Loader Valve

205140
Fig 60.

E-89 9803/9960-1 E-89

 Section E - Hydraulics
Valves
Loader Valve

Main Relief Valve and Auxiliary Relief Valves

205090-B1
Fig 61.

Note: The M.R.V. X and loader valve A.R.V.'s Y are Renew all 'O' rings. Lubricate parts with Hydraulic Fluid
identical in design. before assembly.

Removal The M.R.V. can be tested/adjusted in situ . The A.R.V's are

tested/adjusted on a bench.
Remove rear floor plates. See Floorplates, Section 3.
Replacement
Ensure that the engine is stopped and hydraulic pressure
released from the system. Replacement is a reversal of the removal procedure.

Each valve is removed by unscrewing nut 1. Torque Settings

Dismantling and Assembly Item Nm kgfm lbf ft

The manufacturers do not recommend renewing individual 1 44.75 4.6 33

components of the M.R.V. or A.R.V.'s. Each valve should
be renewed as a unit if a component is defective.

E-90 9803/9960-1 E-90

 Section E - Hydraulics
Valves
Excavator Valve

Excavator Valve

205170
Fig 62.

Dismantling and Assembly ( E-92)

E-91 9803/9960-1 E-91

 Section E - Hydraulics
Valves
Excavator Valve

Dismantling and Assembly Relief Valves

The numerical sequence shown on the illustration is Ensure that A.R.V's 4J to 4T are correctly adjusted and
intended as a guide to dismantling. fitted in their specified positions.

Fig 62. ( E-91) Torque tighten A.R.V's to 41 - 68 Nm (30 - 50 lbf ft, 4.15 -
6.9 kgf m).
For assembly the sequence should be reversed.
The manufacturers do not recommend renewing individual
Check Valves components of the A.R.V.'s. Each valve should be
renewed as a unit if a component is defective.
Each spool has an identical load hold check valve which
can be removed as shown at 4W. Renew all 'O' rings. Lubricate parts with Hydraulic Fluid
before assembly.
Note: Only 4W shown on illustration.
The A.R.V's are tested/adjusted on a bench. Auxiliary
Ensure good condition of seating face on poppet 10 and on Relief Valve (A.R.V.'s) - Using Hand Pump ( E-67)
the mating face in the valve block.
Hydraclamp Valve
Note: All valve block adapters are torqued to 81 Nm (60 lbf
The numerical sequence shown on the illustration is
intended as a guide to dismantling.
Spools
Fig 63. ( E-93)
Spools 4B, 4C, 4D, 4E, 4F and 4G are identical but must
not be interchanged as they are matched to their bores. For assembly the sequence should be reversed.
Slew spool 4A is different in design from the above spools.

All spools have the same centring and sealing components

items 11 to 19 and 24 to 27.

To completely dismantle a spool, follow the sequence 11 to

19 and 24 to 27. To prevent spool rotation when turning
screw 13, hold a rod through the eye end of the spool.

Lubricate new seals with Hydraulic Fluid and take care to

prevent them from being damaged by the sharp edges of
the spool.

Apply JCB Lock and Seal to threads of screw 13.

Torque Settings

Item Nm kgfm lbf ft

1A 17.6 - 20.4 1.76- 2.04 13 - 15
1B 41 - 49 4.2 - 5 30 - 36
11 6.1 - 7.5 0.62 - 0.76 4.5 - 5.5
13

E-92 9803/9960-1 E-92

 Section E - Hydraulics
Valves
Excavator Valve

S175600
Fig 63.

E-93 9803/9960-1 E-93

 Section E - Hydraulics
Valves
Excavator Valve
When Dismantling

Plug hose 1 to prevent loss of oil and entry of dirt.

When Assembling

Note:
Fig 63. ( E-93)

Ensure that orifice X is clear.

Lubricate new seals with Hydraulic Fluid.

Ensure that plug 7 locates in groove Y of rotary spool 9.

Torque nut 5 finger-tight before locking lever 4.

Ensure that spool 9 rotates freely after tightening nuts 5

and 3.

Torque Settings

Item Nm kgfm lbf ft

3 55 - 67 5.6 - 6.84 40.5 - 49.5
7 3.3 - 4.7 0.35 - 0.49 2.5 - 3.5
14

E-94 9803/9960-1 E-94