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.
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