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New Holland Tractor Workmaster 50 / Workmaster 60 / Workmaster 70 / Tier 4B (final). SERVICE MANUAL - page 12

Hydraulic systems - Hydraulic hand control

Hydraulic hand control - Overview

This is a live hydraulic system, where gear type hydraulic

pump is mounted directly to timing case. transmission

lubrication oil is used also as hydraulic oil. This system

described here mechanically senses changes in the draft

loading via the top link of the three point linkage. The

system allows the operator to select position control, draft

control, mixed control and float.

CAUTION

Hydraulic filter is to be changed at regular intervals as

recommended. Hydraulic and transmission parts may

get damaged if filter is choked. Always use genuine

NEW HOLLAND filters.

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The system is operated by position control lever (1), draft

control lever (2), and response control (3).

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NOTE: Some mounted or semi-mounted equipment may

interfere with and cause damage to tractor sheet metal.

To avoid damage check for clearance between tractor and

implements.

Position control operation

Position control provides accurate control of implements

such as sprayers, rakes, rotary tillers, etc. that operate

above the ground. Once set, position control will maintain

the selected implement height.

NOTE: Always set the system to position control at any

time when not actually operating in draft control, such

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as when attaching or transporting equipment or when no

equipment is attached.

Move the draft control lever (1) fully forward in the quad-

rant. Set the required implement height/depth using the

position control lever (2). Pull the lever back to raise

the implement, push forward to lower. Implement height/

depth is relative to the position of the lever in quadrant.

An adjustable stop (3) is provided to enable the lever to

be returned to the required working position.

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Hydraulic systems - Hydraulic hand control

Draft control operation

Draft control is most suitable for mounted or semi-

mounted implements operating in the ground. Changes

in the working depth or changes in soil resistance will

cause draft loading on the implement to increase or

decrease.

Move the position control lever (1) fully forward. Lower

the implement in to the work using draft control lever (2).

Push the lever forward to increase the draft loading. Pull

rearwards to reduce the draft loading. Forward movement

of the draft control lever will increase the implement depth

and rearward movement will reduce the depth.

GNIL14TR00814AA

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Once set, tractor hydraulic system will automatically ad-

just the implement depth to maintain an even pull on the

tractor and minimise wheel slip.

Combined position and draft control opera-

tion

On very light soil or varying soil types in the same field,

it may be necessary to use the draft control and position

control in combination. When starting work, lower the im-

plement to the required depth by means of the draft control

lever (1).

When the implement reaches the required depth, raise

the position control lever (2) back until the lift arms tend to

rise. The lift linkage is now in draft control but the position

control function prevents the system from sinking too deep

when draft reduces.

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Float operation

Move the position control lever (1) and the draft control

lever (2) fully forward. The 3-point linkage will now be

free to ‘float’ or follow the ground contour, a feature useful

for scraper blades etc.

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Response control

The response control knob (1) varies the speed of drop of

the lower links.

Clockwise rotation - Decreases speed of drop

Anti-clockwise rotation - Increases speed of drop

NOTE: To lock implements in transport position when driv-

ing on road, fully raise position control lever (1), 6 and

screw in (rotate clockwise) knob (1), 7.

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Hydraulic systems - Hydraulic hand control

Hydraulic hand control - Disassemble

WARNING

Avoid injury!

Handle all parts carefully. Do not place your hands or fingers between parts. Use Personal Protec-

tive Equipment (PPE) as indicated in this manual, including protective goggles, gloves, and safety

footwear.

Failure to comply could result in death or serious injury.

W0208A

Lift external controls can be disassembled and re-

assembled only with the lift on a work bench or on

a rotary stand. It is possible to remove only position

control lever when the lift assembly is mounted on the

tractor.

1. Remove the lift from the transmission housing and

place on a work bench or fix on a rotary stand.

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2. Loosen set screws (1) and remove position control

lever hub along with nylon washer.

NOTE: Nylon washers can be removed from hub by loos-

ening Allen screw.

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3.

1. After loosening set screws remove position control

lever (1).

2. Remove bolts (2) to take out sector plate.

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Hydraulic systems - Hydraulic hand control

4.

1. Remove draft control lever hub by loosening set

screws (1) along with the nylon washer.

2. Remove sector plate.

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4

5. Draft control lever is welded on draft control shaft. Re-

move the position control shaft and draft control shaft

to remove the draft control lever internal linkages.

1. Remove set screw.

2. Remove linkages from the shafts.

NOTE: Remove hydraulic linkages to remove set screw.

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6. Remove set screw (1) to remove shaft.

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Hydraulic systems - Hydraulic hand control

Hydraulic hand control - Assemble

1. Reassemble the lift external controls following the dis-

assemble procedure in reverse.

2. Check the O-rings on the draft control shaft for any

damage. If necessary, replace by new O-rings.

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Hydraulic systems - Main control valve

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Hydraulic systems - Main control valve

B. Lifting phase

During this phase, the control valve supplies the oil under pressure to the cylinder (9) and it consequently lifts the

arms.

The control spool (1) is in such a position to connect the chamber (5) of the differential valve (2) with the oil coming

from the pump through annular duct (8) and holes (12) and (13) making in this way the valve itself to close.

The oil from the pump finding the differential valve (2) closed goes to cylinder, pass the hole (14) opens the check

valve (3) enters in the annular duct (11) and enters the chamber (9).

The lifting speed depends on the pump RPM.

In this phase the maximum lifting pressure is controlled by the safety valve (15) that is connected to annular duct (8)

through hole (14) and then to the oil inlet.

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Hydraulic systems - Main control valve

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Hydraulic systems - Main control valve

Main control valve - Remove (Distributor assembly)

WARNING

Avoid injury!

Handle all parts carefully. Do not place your hands or fingers between parts. Use Personal Protec-

tive Equipment (PPE) as indicated in this manual, including protective goggles, gloves, and safety

footwear.

Failure to comply could result in death or serious injury.

W0208A

1. Loosen the bolts (1) and remove distributor assembly

from lift housing.

NOTE: Distributor assembly is not serviceable. Replace

complete assembly if found defective.

2. Insert the distributor assembly back on the lift assembly

and tighten the bolts (1).

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NOTE: Check the O-rings (1) for any damage on distributor

assembly before installing and replace if required.

GNIL14TR04649AB

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Steering - Steering control

Steering control - Special tools

Description

Tool number

Steering wheel puller

380001672 and 380003008

Adapter, power steering pressure check

291318

(includes in the set of hydraulic pressure kit 292870)

Power steering rotor spring installer

292927

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Steering - Steering control

Steering control - Overview - Hydrostatic steering

GNIL14TR00870FA

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D1. Control valve

P. Hydraulic pump

E. Filter cartridge

S. Return to tank

H. Power cylinder

T. Reservoir

M. Pump outlet line

V. Steering wheel

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Steering - Steering control

GNIL14TR04488JB

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Steering - Steering control

Operation of the above valves eliminates continuous steering wheel correction and prevents front wheel shimmy,

hydraulic circuit failure and damage to the steering linkage.

GNIL14TR04489FB

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Steering - Steering control

Steering control - Troubleshooting

Problem

Possible Cause

Correction

Steering wheel is heavy

No or insufficient oil pressure

to turn

a) Pump does not run

Start up pump (loose V-belt)

b) Pump defective

Repair or replace pump

c) Pump runs in the wrong

Correct direction of rotation of pump or re-

the direction

place pump

d) Pump is worn out

Replace pump

e) Pump is under dimensioned

Install a larger pump (examine pressure

need and flow)

Pressure relief valve is stuck in open posi-

Repair or clean pressure relief valve. Ad-

tion or setting pressure is too low

just the valve to the correct pressure

Priority valve is stuck in open position

Repair or clean the priority valve

Too much friction in the mechanical parts of

Lubricate bearings and joints of steering

the vehicle

gear or repair if necessary. Check steer-

ing column installation

Emergency steering balls missing

Install new balls

Combination: Downstream system + steer-

Change cylinder type (through going piston

ing unit with suction valve and differential

rod). If necessary use two differential cylin-

cylinder are inexpedient

ders

Hard point when starting

Spring force in priority valve too weak

Replace spring by a stronger one ( 4 bar

to turn the steering wheel

(58 psi)

,

7 bar

(102 psi) and

10 bar

(145 psi))

Air in LS and /or PP pipes

Bleed LS and PP pipes

Clogged orifices in LS or PP side priority

Clean orifices in spool and in connecting

valve

plugs for LS and PP

Oil is too thick (cold)

Let motor run until oil is warm

Regular adjustments of

Leaf spring without spring force or broken

Replace leaf springs

the steering wheel are

necessary (“snake-like

driving”)

Spring in double shock valve broken

Replace shock valve

Gear wheel set worn

Replace gear wheel set

Cylinder seized or piston seals worn

Replace defective parts

Neutral position of

Steering Column and steering unit out of

Align the steering column with steering unit

steering wheel cannot

line

be obtained, i.e. there is a

tendency of “Motoring”

Too little or no play between steering col-

Adjust the play and, if necessary, shorten

umn and steering unit input shaft

the splines journal.

Pinching between inner and outer spools

Contact your authorised NEW HOLLAND

“Motoring” effect. The

Leaf springs are stuck or broken and have

Replace leaf springs

steering wheel can turn

therefore reduced spring force

on its own

Inner and outer spools pinch, possible due

Clean steering unit or contact your NEW

to dirt

HOLLAND dealer

Return pressure in connection with the

Reduce return pressure, change cylinder

reaction between differential cylinder and

type or use a non-reaction control unit

steering unit too high

Backlash

Cardan shaft fork worn or broken

Replace cardan shaft

Leaf springs without spring force or broken

Replace leaf springs

Worn splines on the steering column

Replace steering column

“Kick-back” in steering

Fault in the system

Contact your authorised NEW HOLLAND

wheel from system. Kicks

from wheels

Heavy kick-back in

Wrong setting of cardan shaft and gear

Correct setting as shown in service manual

steering wheel in both

wheel set

directions

Turning the steering

Hydraulic hoses for the steering cylinders

Reverse the hoses

wheel activates the

have been switched around

steered wheels opposite

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Steering - Steering control

Problem

Possible Cause

Correction

“Shiny” - effect. The

Air in the steering cylinder

Bleed cylinder. Find and remove the rea-

steered wheels vibrate.

son for air collection

(Rough tread on tires

gives vibrations)

Mechanical connections or wheel bearings

Replace worn parts

worn

Steering wheel can be

Oil is needed in the tank

Fill with clean oil and bleed the system

turned the whole time

without the steered

wheels moving

Steering cylinder worn

Replace or repair cylinder

Gear wheel set worn

Replace gear wheel set

Spacer across cardan shaft forgotten

Install spacer

Steering wheel can be

One or both anti-cavitation valves are leaky

Clean or replace defect or missing valves

turned slowly in one or

or are missing in OSPC or OVP/OVR

both directions without

the steered wheels turning

One or both shock valves are leaky or are

Clean or replace defective or missing

missing in OS PC or OVP/OVR

valves

Steering is too slow and

Insufficient oil supply to steering unit, pump

Replace pump or increase number of revo-

heavy when trying to turn

defective or number of revolutions too low

lutions

quickly

Relief valve setting too low

Adjust valve to correct setting

Relief valve sticking owing to dirt

Clean the valve

Spool in priority valve sticking owing to dirt

Clean the valve, check that spool moves

easily without spring

Too weak spring in priority valve

Replace spring by a stronger (There are 3

sizes:

4 bar (58 psi), 7 bar (102 psi) and

10 bar (145 psi)

Too little steering force

Pump pressure too low

Correct pump pressure

(possibly to one side only)

Too little steering cylinder

Fit a larger cylinder

Piston rod area of the differential cylinder

Fit cylinder with thinner piston rod or 2 dif-

too large compared with piston diameter

ferential cylinders

Leakage at either

Shaft defective

Replace shaft seal

input shaft, end cover,

gear-wheel set, housing

or top part

Screws loose

Tighten screws Torque 3-3, t daNm or

steering unit (2, 5-3 daNm)

Washers or O-rings defective

Replace washers and O-rings

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Steering - Hydraulic control components

Hydraulic steering oil reservoir - Remove

1. Lift the front hood.

2. Disconnect the hoses from the steering oil reservoir.

GNIL14TR00758AA

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3. Loosen the bolts and remove the steering oil reservoir.

GNIL14TR00759AA

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Steering - Hydraulic control components

Power steering control valve - Remove

1.

Position the tractor on a hard level surface and apply

the parking brake.

WARNING

Avoid injury!

Handle all parts carefully. Do not place your

hands or fingers between parts. Use Personal

Protective Equipment (PPE) as indicated in this

manual, including protective goggles, gloves,

and safety footwear.

Failure to comply could result in death or seri-

ous injury.

W0208A

2.

To gain access to the steering motor:

• Remove tractor rear hood

• Remove fuel tank

For removal procedure, please refer to Engine section.

3.

1. Remove the four bolts (1) at the base of the steering

column.

2. Slide out the steering motor from the steering col-

umn.

3. Remove bolts (2) from bracket to take out starting

motor.

4 Disconnect the four steering pipes (3).

GNIL14TR00740AA

1

Disconnect the four supply / return tubes and O-ring

seals from the steering motor

2. Cap the ends of the tubes and steering motor to

prevent entry of foreign particles.

T - To tank

P - From pump

L - Left port

R - Right port

GNIL14TR04490AB

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Steering - Hydraulic control components

Power steering control valve - Disassemble

1. Hold the steering securely in a vice.

2. Remove the end cover bolts (6 plus one special screw).

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3. Remove the end cover, sideways.

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4. Lift the gear wheel set (with spacer fitted) off the unit.

Take out the two O-rings.

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5. Remove cardan shaft.

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Steering - Hydraulic control components

6. Remove distributor plate.

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7. Screw out the threaded bush over the check valve.

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8. Remove O-ring.

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9. Shake out the check valve ball and suction valve pins

and balls.

NOTE: Replace pins prior to the reassembly.

GNIL14TR04499AA

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Steering - Hydraulic control components

10. Take care to keep the cross pin in the sleeve and spool

horizontal. The pin can be seen through the open end

of the spool. Press the spool inwards and the sleeve,

ring, bearing races and needle bearing will be pushed

out of the housing together.

GNIL14TR04500AA

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11. Take ring, bearing races and needle bearing from

sleeve and spool. The outer (thin) bearing race can

sometimes “stick” in the housing, therefore check that

it has come out.

GNIL14TR04501AA

10

12. Press out the cross pin. Use the special screw from

the end cover.

GNIL14TR04502AA

11

NOTE: A small mark has been made with pumice stone on

both spool and sleeve close to one of the slots for the neu-

tral position springs (see figure). If the mark is not visible,

remember to leave a mark of your own on sleeve and spool

before the neutral position springs are dismantled.

GNIL14TR04503AA

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Steering - Hydraulic control components

13. Carefully press the spool out of the sleeve.

GNIL14TR04504AA

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14. Press the neutral position springs out of their slots in

the spool.

GNIL14TR04505AA

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15. Remove dust seal and O-ring /kin-ring /roto glyd.

GNIL14TR04506AA

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16. The steering unit OSPB is now completely dismantled.

GNIL14TR04507AA

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