DAF CF65, CF75, CF85 Series . Manual — part 932

©

200423

1-5

General

BRAKING PERFORMANCE AND BRAKE EQUALISATION

ΧΦ65/75/85 series

6

6

1.3 BRAKE EQUALISATION BY MEANS OF BRAKE DYNAMOMETER

1.

Make sure the vehicle combination is in
laden condition. A laden combination
makes for a more reliable and accurate
measurement. Furthermore, the maximum
braking performance will be achieved when
the vehicle combination is in laden condition.

2.

The braking forces must be measured on a
system with warm brakes. (Normal operating
temperature for drum brakes

90C for disk

brakes

150C.)

3.

The brake linings must have been bedded in.
Only then can a reliable verdict on the
braking forces be obtained.

4.

Write down the braking forces of the various
axles on the "brake equalisation form for
brake dynamometer" at the following braking
pressures, measured at the service coupling
head:
p = 0.5 - 1.0 - 1.5 - 2.0 - 3.0 - 4.0 - 5.0 bar

5.

Using the data on the "brake equalisation
form for brake dynamometer", calculate the
braking deceleration percentages.

6.

Plot the calculated values in the "brake
equalisation form for brake dynamometer"
in the appropriate EC band graph and
evaluate the measured brake equalisation.

p

R600028

BRAKING PERFORMANCE AND BRAKE EQUALISATION

1-6

©

200423

General

6

ΧΦ65/75/85 series

6

1.4 BRAKE EQUALISATION FORM FOR BRAKE DYNAMOMETER

R600119

R

L

L

R

L

R

0.5

1.0

1.5

2.0

3.0

4.0

5.0

%

%

%

%

%

%

%

R

L

L

R

L

R

0.5

1.0

1.5

2.0

3.0

4.0

5.0

%

%

%

%

%

%

%

p

p

p

p

m 1 + m 2 + . . . . . .

m 1 +

m 2 + . . . . . .

m 1 + m 2 + . . . . . .

m 1 +

m 2 + . . . . . .

R

L

R

L

R

L

R

L

R

L

R

L

F1

F2

F3

F1

F2

F3

F1+F2+F3

m 1 + m 2 + . . . . . .

F1+F2+F3

X 100 %

F1+F2+F3

X 100 %

m 1 + m 2 + . . . . . .

F1+F2+F3

©

200423

1-7

General

BRAKING PERFORMANCE AND BRAKE EQUALISATION

ΧΦ65/75/85 series

6

6

Filling in brake equalisation form for brake
dynamometer

Note:
1 kg = 10 newtons (N)

1.

Determine the weight of the laden prime
mover and/or trailer vehicle (coupled),
and enter these values in the table (in kg or
newtons).

2.

Make a short test run to warm up the brakes.

3.

Position the vehicle, starting with the front
axle, on a brake dynamometer.

4.

Connect a pressure gauge to the yellow
coupling head.

5.

Depress the brake pedal until the pressure
gauge reading is 0.5 bar.
Always build up pressure, i.e. from low to
high pressure, and never from high pressure
to low pressure, and always begin every
measurement with 0 bar.

6.

Read the braking forces and write them
down in the appropriate column (in kg or
newtons).

7.

Now repeat this procedure at pressures of
1.0 - 1.5 - 2.0 - 3.0 - 4.0 and 5.0 bar.

8.

Also perform these measurements on all
other vehicle axles.

9.

Count all braking forces that belong to a
certain braking pressure and note these in
the "Total braking force" column.

10. Divide the braking forces (in kg or newtons)

just entered at point 9 by the weight of the
vehicle (in kg or newtons), multiply the result
by 100 (%) and enter the values thus
obtained in the next column.
braking deceleration as % of the weight

11. Plot the values obtained in point 10 in the

relevant EC tyre graph.

F

p

R600029

BRAKING PERFORMANCE AND BRAKE EQUALISATION

1-8

©

200423

General

6

ΧΦ65/75/85 series

6

Example of a diagram for a prime mover and
trailer vehicle with poor brake balance.

Example of a diagram for a prime mover and
trailer vehicle with correct brake balance.

The combination is correctly balanced if the
braking performance at 2 - 3 bar for the truck and
the trailer vehicle are in a comparable position in
the appropriate EC band, i.e. both in the upper
part, both in the lower part or both in the middle
part.

%

a

40

30

20

10

0

1

0

2

3

4

5 bar

p

%

a

40

30

20

10

0

1

0

2

3

4

5 bar

p

R600022