DAF CF65, CF75, CF85 Series . Manual - part 946

©

 200423

1-3

Steering gear, general

DIAGNOSTICS

ΧΦ65/75/85 series

7

1

SYMPTOM: WHEEL DEFLECTION TOO SMALL

Possible cause

Remedy

The vehicle is being steered when at a standstill

Steer while the vehicle is moving.

Incorrect setting of maximum wheel deflection at 

the axle

Check maximum wheel deflection and - if 

incorrectly set - correct it.

Wheel deflection limiting valves incorrectly 

adjusted

Check setting of the wheel deflection limiting 

valves.

Axle load of steerable axle(s) too high

Check axle load(s).

Adjust the load.

System pressure too low

Check maximum system pressure.

Replace pressure-limiting valve or steering pump.

Steering rod incorrectly set

Check steering rod setting.

Pitman arm installed in the wrong position on 

steering box output shaft

Check whether position of pitman arm on the 

sector shaft is correct, using the markings.

Wrong pitman arm installed on steering box

Check the pitman arm part number.

Sector shaft is installed in the wrong position in the 

steering box

Put steering box in the central position and check 

whether the sector shaft is correctly installed, using 

the markings on the input shaft and on the sector 

shaft.

SYMPTOM: VEHICLE PULLS TO ONE SIDE

Possible cause

Remedy

Unequal weight distribution causing the vehicle to 

tilt

Adjust the weight distribution.

Firth-wheel coupling insufficiently lubricated

Lubricate fifth-wheel coupling.

Driving over cambered roads.

When driving over cambered roads, bear in mind 

that the vehicle might pull to one side.

Difference in tyre pressure between the wheels on 

the steerable axle(s)

Check the tyre pressure. Pump both tyres to the 

specified value.

Different tyre types or difference in tread depth 

between tyres of the steerable axle(s)

Always fit tyres of the same type and tread depth 

on the axle.

Different wheel rims installed on the steerable 

axle(s)

Always install wheel rims of the same type on the 

axle.

Fault in one of the tyres

Replace the tyre on the side the vehicle pulls to.

Incorrectly adjusted brakes or a brake of the 

steerable axle(s) which is "dragging".

Check brakes. If necessary repair and re-adjust.

Misalignment of the universal joints of the steering 

column

Check/adjust position of the universal joints in 

relation to each other.

Poorly adjusted wheel bearing play

Check wheel bearing adjustment. Adjust the wheel 

bearing play until correct.

Incorrect caster

Check caster. Adjust caster until correct.

Incorrect camber angle

Check camber angle.

Check axle housing.

DIAGNOSTICS

1-4

©

 200423

Steering gear, general

1

ΧΦ65/75/85 series

7

Incorrect alignment of steerable axles

Check alignment of the steerable axles. Adjust 

steering rods until correct.

Incorrect alignment of rear axle(s) or of trailer/

semi-trailer

Check alignment of the rear axle(s) or of trailer/

semi-trailer. Align axles.

Front axle/rear axle suspension play

Check suspension. Replace worn parts.

Difference in spring opening between the leaf 

springs of one axle

Measure the spring opening of the springs.

Replace springs.

Poorly adjusted air suspension. This will cause the 

vehicle to tilt.

Check height adjustment. Adjust the height until 

correct.

Steering pump output too high.

Check pump output.

Check the flow control valve for smooth operation.

Incorrect hydraulic central position of the steering 

box

Check the hydraulic central position of the steering 

box.

The hydraulic centre position cannot be set.

Replace the steering box.

SYMPTOM: VEHICLE IS SEARCHING, TRACKING INSTABILITY

Possible cause

Remedy

Tyre pressure of steerable wheels too low

Check the tyre pressure.

Increase tyre pressure to the specified value.

Fifth-wheel coupling insufficiently lubricated or 

damaged

Inspect/lubricate fifth-wheel coupling.

Incorrect steering box pressure point setting; play 

at the pressure point or pressure point set too tight

Check pressure point setting. Adjust pressure 

point until correct.

Axle load of front axle too low

Check axle load and adjust the load.

Incorrect toe-in

Check toe-in.

Adjust toe-in until correct.

Incorrect caster

Check caster.

Adjust caster until correct.

Incorrect alignment of 2nd steerable axle

Check alignment of 2nd steerable axle.

Adjust alignment until correct.

Play in a universal joint or in the steering column 

slide joint. Tight universal joint

Check universal joints and the steering column 

slide joint. Replace worn parts.

Misalignment of the universal joints in the steering 

column

Check/adjust position of the universal joints in 

relation to each other.

Play in the steering rod ball joints

Check ball joints.

Replace ball joint.

Loose steering box, steering bracket or steering 

rod attachment

Check attachments, retighten bolts/nuts.

Worn or tight swivel axle bearing

Check swivel axle bearing.

Replace worn parts.

SYMPTOM: VEHICLE PULLS TO ONE SIDE

Possible cause

Remedy

©

 200423

1-5

Steering gear, general

DIAGNOSTICS

ΧΦ65/75/85 series

7

1

Steering rod set incorrectly; when the wheels are in 

the "straight ahead" position, the steering box is 

not in its mechanical central position (pressure 

point)

Check steering rod setting.

Adjust steering rod until correct.

Front axle/rear axle suspension play

Check axle suspension. Replace worn parts.

Steering pump output too high

Check steering pump output.

Check the flow control valve for smooth operation.

If necessary, replace steering pump.

Excessive internal steering box resistance.

Check internal steering box resistance.

Replace steering box.

Internal defect in the steering box

Replace steering box.

SYMPTOM: STEERING WHEEL DOES NOT RETURN TO THE 

"STRAIGHT AHEAD" POSITION (OR ONLY VERY SLOWLY)

Possible cause

Remedy

Tyre pressure of steerable wheels too low

Check the tyre pressure.

Increase tyre pressure to the specified value.

Fifth-wheel coupling insufficiently lubricated or 

damaged

Inspect/lubricate fifth-wheel coupling.

Misalignment of the universal joints of the steering 

column

Check/adjust position of the universal joints in 

relation to each other.

Axle load of front axle too low

Check axle load and adjust the load.

Incorrect caster

Check caster.

Adjust caster until correct.

Tight universal joint or steering column bearing

Check universal joints and steering column 

bearing. Replace worn parts.

Friction between mechanical parts of the steering 

gear (pitman arm, steering rod/steering arm or 

track rod/track rod arm)

Check mechanical parts of the steering gear.

Loose steering box or steering bracket

Check attachments, retighten bolts.

Tight swivel axle bearing

Check swivel axle bearing.

Steering pump output too high

Check pump output.

Check the flow control valve for smooth operation.

Replace pump.

Pressure point set too tight

Check pressure point setting. Adjust pressure 

point until correct.

Excessive internal steering box resistance

Check internal steering box resistance.

Replace steering box.

Internal defect in the steering box

Replace steering box.

SYMPTOM: VEHICLE IS SEARCHING, TRACKING INSTABILITY

Possible cause

Remedy

DIAGNOSTICS

1-6

©

 200423

Steering gear, general

1

ΧΦ65/75/85 series

7

SYMPTOM: CIRCUIT 1 WARNING SYMBOL REMAINS ACTIVATED

Possible cause

Remedy

Defective output indicator

Remove cover of circuit 1 reservoir and, with the 

engine at idling speed, check if oil has returned.

If in doubt, check main steering pump output.

Replace output indicator.

Circuit 1 oil level too low

Check the oil level.

Top up oil and bleed system.

There is air in the system.

Bleed the system.

Steering oil lines of circuit 1 kinked or pinched off

Check/re-adjust routing of the steering oil lines.

Main steering pump output too low

Check main steering pump output.

Replace main steering pump.

Fault in warning system

Check/repair warning system.

SYMPTOM: CIRCUIT 2 WARNING SYMBOL REMAINS ACTIVATED

Possible cause

Remedy

Defective output indicator

Carry out function test for the emergency steering 

gear.

Replace output indicator.

Circuit 2 oil level too low

Check the oil level.

Top up oil and bleed system.

There is air in the system.

Bleed the system.

Steering oil lines of circuit 2 kinked or pinched off

Check/re-adjust routing of the steering oil lines.

Emergency steering pump output too low

Check emergency steering pump output.

Replace emergency steering pump.

Fault in warning system

Check/repair warning system.

SYMPTOM: JOLTING OF THE STEERING WHEEL

Possible cause

Remedy

Air in the system

Check steering oil level and bleed system.

Worn or loose shock absorbers on the steerable 

axle(s)

Tighten attachment.

Replace shock absorbers.

Steering pump output too low

Check steering pump output.

Loose steering rod, track rod, steering bracket or 

steering box

Check/tighten attachment of these components.

Excessive internal steering box play

Check the input shaft play.

Check the steering box pressure point.

Replace the steering box.