DAF CF65, CF75, CF85 Series . Manual - part 1107

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1-1

General

REAR AXLE ALIGNMENT

ΧΦ65/75/85 series

9

6

1. GENERAL

1.1 DESCRIPTION OF POSSIBLE CAUSES OF REAR AXLE MISALIGNMENT

The drawing above shows several factors which 

determine the position of the axle under the 

vehicle:

1.

Difference in spring opening between the 

spring assemblies on the left and right as a 

result of the composition of the spring 

assemblies, or of an unbalanced vehicle 

load.

2.

Play between the centre bolt and the spring 

assembly.

3.

Location of the holes in the chassis for the 

attachment of the spring bracket.

4.

Dimensions of the spring bracket.

5.

Dimensions of the spring eye.

6.

Installation of spring assembly to the axle 

housing.

?

2

1

3

4

5

6

C900386

REAR AXLE ALIGNMENT

1-2

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General

6

ΧΦ65/75/85 series

9

Points 2 to 6 are factors determined by the 

manufacturer. Generally, the manufacturer will 

ensure that the axle is (within a narrow margin) 

positioned at an angle of 90

 in relation to the 

central axis of the chassis.

Point 1, however, cannot always be controlled by 

the manufacturer.

The difference in spring opening, which is 

minimal for new spring assemblies, may increase 

as a result of the "settling" of the spring assembly.

Furthermore, the superstructure and vehicle load 

may be the cause of a difference in spring 

opening and, consequently, misalignment of the 

axle.

During spring movement the axle moves 

backwards. If the springs on one side deflect 

more than on the other side because of an 

unbalanced vehicle or superstructure, this side of 

the axle will move further backwards than the 

other. As a result, the axle will no longer be at 

right angles to the centreline of the vehicle.

The misalignment of the rear axle(s) may result in 

increased tyre wear.

In case of a combination (truck and trailer or a 

tractor and semi-trailer), a misaligned trailer or 

semi-trailer may cause increased tyre wear on 

the drawing vehicle.

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Inspection and adjustment

REAR AXLE ALIGNMENT

ΧΦ65/75/85 series

9

6

2. INSPECTION AND ADJUSTMENT

2.1 INSPECTION AND ADJUSTMENT, AXLE ALIGNMENT

General
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Use only high-quality testing tools for 

measurements. They must be calibrated 

regularly and preferably be of the type that 

can be calibrated before every use.

-

Position the vehicle on a flat and level 

surface during the measurement.

-

Work with great accuracy.

-

Check the position of each wheel relative to 

the centreline of the vehicle (twin wheels are 

regarded as one wheel).

-

The misalignment of a rear axle is equal to 

the average of the individual misalignments 

of the left and right rear wheels.

-

For a vehicle combination (truck with trailer, 

or tractor with semi-trailer), the alignment of 

the vehicle combination as a whole must be 

checked. A misaligned trailer or semi-trailer 

may cause problems for the tractor.

Inspection of axle alignment
1.

Make sure that the load being carried is 

representative of normal vehicle operation. 

The load must be at least 40% of the 

permissible loading weight and be evenly 

distributed over the vehicle.

2.

Drive the vehicle straight to the test location 

to avoid stresses in the chassis or in the axle 

suspension system.

Note:

Avoid braking hard and do not put the vehicle 

on the parking brake.

3.

Check the tyre pressure prior to the 

measurement. Adjust if necessary.

4.

Check the spring opening of the spring 

assembly and check the axle suspension for 

play. Any defects should be repaired first.

5.

Consult the measuring tool instructions for 

use and adhere to them.

6.

Calibrate the testing tool, if possible.

7.

Use the testing tool to measure the position 

of each rear axle wheel in relation to the 

vehicle centreline in mm/m.

REAR AXLE ALIGNMENT

2-2

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Inspection and adjustment

6

ΧΦ65/75/85 series

9

8.

Determine the position of the rear axle 

relative to the vehicle centreline, on the basis 

of the positions of the two wheels.

9.

Check that the outcome is within the 

permitted tolerance limits. If the 

misalignment of the axle is beyond this limit, 

the axle alignment needs to be adjusted.

10. If two or more rear axles are fitted, check the 

position (non-parallelism) of the rear axles to 

each other.

11. Check that the outcome is within the 

permitted tolerance limits. If the 

misalignment (non-parallelism) of the axle is 

beyond this limit, the axle alignment needs to 

be adjusted.

Determining the axle alignment
A practical aid to visualise the position of the axle 

is the test report at the end of this section.

Mark the test readings as shown below.

Example 1
1.

Mark the test readings in the scales at the top 

and side of the measured wheel.

In the opposite example (drawing 1) the 

misalignment has been determined as a 3 

mm/m toe-out in relation to the vehicle 

centreline for the left wheel and a 3 mm/m 

toe-in in relation to the vehicle centreline for 

the right wheel.

2.

From the small circle at the bottom of the 

wheel, draw a straight line to the test reading 

indicated on the wheel top scale. This should 

be done for both wheels (drawing 2).

The (mis)alignment of the wheels relative to 

the vehicle centreline is now visible.

Drawing 1

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+

+

-

-

+

+

-

3

3

3

3

W908002

Drawing 2

-

+

+

-

-

+

+

-

3

3

3

3

W908003