Most Frequent Axle Errors Of A Vehicle - Nussbaum WA 950 Instrucciones De Uso

Turn difference
Difference of the steering deflection angles of
the front wheels.
Is measured, by agreement, with an inward-
curving wheel at a steering deflection of 20°.
Unit of measurement degrees.
Set back of an axis
Position difference of the wheels to the verti-
cal of the longitudinal axis of the vehicle.
There is a front and rear wheel setback; the
latter is not to be confused with the geometric
axis of travel. Unit of measurement degrees.
Geometric thrust
Angle between the axis of symmetry and the
direction of travel of the rear axle. Is obtained
from the bisectors of the two rear trail angles.
Unit of measurement degrees.
Turn difference
The angle formed by the line joining the
attachment points of the left front and rear
wheels and the line joining the attachment
points of the right-hand front and rear wheels
of the vehicle.
Unit of measurement in degrees or millimeters
respectively when the wheel base is known.
Wheel base difference
The angle formed by the joining lines of the
attachment points of the front wheels and
those of the rear wheels.
Unit of measurement in degrees or millime-
ters, when the wheel base is known.
Lateral offset
The angle formed by the line joining the
attachment points of the left-hand or right-
hand front and rear wheel and the axis of
symmetry of the vehicle.
Unit of measurement in degrees or millime-
ters, when the wheel base is known.
Axis offset
The angle formed by the bisector of the track
difference angle and the axis of travel of the
vehicle.
Unit of measurement in degrees or millime-
ters, when the wheel base is known.
96
14.2

Most frequent axle errors of a vehicle

Vehicle steers off towards the left or right.
Cause: Tire drift.
Exchange the wheels of the same axle:
When the vehicle then pulls to the other side, the tire of one of
the exchanged wheels should be turned on the wheel rim.
If no change is found as a result of the exchange, interchange
the wheels of the other axis.
If this fault remains even after this double exchange, check the
adjustment of the camber values of an axis, as also that of the
caster.
Steering wheel not aligned with the direction of travel.
Possible causes:
- mechanical backlash
- compensation bad or not carried out at all
- wheel alignment carried out with steering wheel off-center
- misalignment of the front wheels to the axis of symmetry.
- mechanical backlash
- compensation bad or not carried out at all
- wheel alignment carried out with steering wheel off-center
- misalignment of the front wheels to the axis of symmetry.
Vehicle with non-uniform steering turning.
Center the steering wheel housing by counting the revolution
from one full steering deflection to another.
Position the steering wheel exactly in the middle of its total path,
lock it in that position and make the adjustment of the front half-
toes.
The steering wheel may have to be taken off the column for
doing so.
Vehicle with rigid steering at standstill.
Possible causes:
- excessive caster
- S.A.I. (Steering Axis Inclination) is wrong
- excessive camber
Weak or excessively strong steering wheel return move-
ment during driving.
Incorrect caster value, adjust.
Tire wearing.
- Uneven wear and tear on both sides of the tire: wrong or
too low tire pressure.
- Uneven wear in the middle of the tire: wrong or excessi
vely high filling pressure.
- Tires with graduated wear: shock absorbers with low
capacity.
- Tires of the same axle worn unevenly on only one side:
toe values not within the tolerance range.
- Only one tire of the same axle worn unevenly:
Camber not within the tolerance range.
Settings on vehicles with power steering.
Before starting the axle settings, switch on the engine, turn the
steering wheel fully in both directions, then align it correctly and
hold it in that position.
The adjustment can be made as desired either with the engine
running or turned off, unless, according to manufacturer's
specifications this process is only possible with the engine
running.
19.03.2010 1 689 979 873N