DAF CF65, CF75, CF85 Series . Manual — part 1160

©

200423

3-23

Inspection and adjustment

EXPLANATORY NOTES ON THE MAINTENANCE ACTIVITIES

ΧΦ75 series

5

Checking and adjusting load-sensing air-
suspension control valve
1.

Check that the correct valve has been fitted

(see instruction plate).

2.

Connect pressure gauge (4) to the test

connection close to connecting point

 on

the load-dependent control valve (input

pressure).

3.

Connect a pressure gauge (2) to the test

connection on one of the brake cylinders

(service brake connection) of the rear axle.

4.

Connect a pressure gauge (43) with a

pressure-reducing valve to the simulation

connection near connections 41 and 42 of

the load-sensing valve (= simulated

adjustable bellows pressure).

5.

Make sure that the reservoir pressure is

higher than 8.5 bar throughout the testing

process.

6.

Set the simulated bellows pressure to its

second lowest value, as indicated on the

instruction plate.

7.

Depress the brake pedal until pressure

gauge (4) indicates a pressure of 8 bar.

8.

Read the brake pressure of the rear axle on

pressure gauge (2) and check that this brake

pressure matches the one listed on the

instruction plate in the table under "delivery

pressure p2" to the rear axle.

9.

If the measured value is not correct,

depressurise connection (43) and, using a

special tool (DAF no. 1329464), turn the

adjusting nut (s):

-

braking pressure too high: unscrew the

adjusting nut

-

braking pressure too low: screw in the

adjusting nut.

Note:

When depressurising the simulation

connection (pressure gauge 43), the air hose

must remain connected to prevent the

(actual) bellows pressure from accidentally

activating the valve.

The small socket head screw in the centre of

the valve must not be adjusted.

10. Repeat the procedure described in point 6

until the measured braking pressure value is

within the tolerance limits.

43

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4

2

2

R600473

1

41 42

r

s

R600478

EXPLANATORY NOTES ON THE MAINTENANCE ACTIVITIES

3-24

©

200423

Inspection and adjustment

5

ΧΦ75 series

11. Set the simulated bellows pressure to its

second highest value, as indicated on the

instruction plate.

12. Depress the brake pedal until pressure

gauge (4) indicates a pressure of 8 bar.

13. Read the pressure gauge (2) and check that

this braking pressure matches the pressure

indicated in the table on the instruction plate.

14. If the measured reading is not correct,

depressurise connection (43) and turn the

adjusting bolt (r) using a Torx screwdriver:

-

braking pressure too high: screw in the

adjusting bolt

-

braking pressure too low: unscrew the

adjusting bolt.

Note:

When depressurising the simulation

connection (pressure gauge 43), the air hose

must remain connected to prevent the

(actual) bellows pressure from accidentally

activating the valve.

The small socket head screw in the centre of

the valve must not be adjusted.

15. If the adjusting bolt (r) has been turned,

repeat the procedure from point 6.

©

200423

3-25

Inspection and adjustment

EXPLANATORY NOTES ON THE MAINTENANCE ACTIVITIES

ΧΦ75 series

5

3.28 CHECKING AND ADJUSTING LOAD-SENSING LEAF-SPRING CONTROL

VALVE

Explanatory notes on instruction plate
This plate is mounted on the rear door pillar on

the left-hand side of the vehicle. The data on axle

loads and delivery pressures are listed on the

instruction plate in the sequence of the axles

beneath the vehicle. Therefore, "1" refers to the

(first) front axle, "2" to the next following axle, etc.

If the vehicle is fitted with a relay valve in the front

axle brake circuit, the box beneath the valve

illustration will be blank. Throughout the column,

a value of 8.1 bar has been filled in for "delivery

pressure p2" under axle "1".

If the vehicle is equipped with a control valve

instead of the relay valve mentioned, the box will

contain a pressure ratio, e.g."i = 1 : 1.5". The

"delivery pressure p2" of axle "1" then indicates

variable readings.

These values can be used to check the brake

pressure values of the front axle and to carry out

the inspection/adjustment below at the same

time. To do this, connect a pressure gauge to the

test connection of one of the front axle brake

cylinders.

AUTOM. LASTAFHANKELIJKE REMKRACHTREGELING
AUTOM. LOAD SENSING DEVICE
AUTOM. LASTABHAENGIGE BREMSKRAFT REGELEINR.
DISPOSITIF DE CORRECTION AUTOM. DE FREINAGE
REGOLATORE AUTOM. DELLA FORZA FRENANTE
REGULADOR AUTOM. DEL ESFUERZO DE FRENANDA

TYPE - TIPO : FA

1425287

2

1.8

2.0

3.0

4.0

8.0

10.0

11.5

13.0

2

1.8

1.8

2.2

3.1

6.4

7.6

8.2

8.2

1

5.7

5.7

5.8

6.1

7.4

7.8

8.0

8.0

1

ASLAST G

AXLE LOAD

ACHSLAST

CHARGE SOUS ESSIEU

CARICO ASSE

CARGA EJE

x10

4

N

UITGESTUURDE DRUK p2

DELIVER

Y PRESSURE

AUSGESTEUER

TER DRUCK

PRESSION DELIVREE

PRESSIONE USCIT

A

PRESION DE SALIDA

bar

BALG DRUK p3

PRESSURE BELLOWS

BALG DRUCK

PRESSION COUSSIN

PRESS. CUSCINI ARIA

PRESION FUELLES

bar

±0.4

±0.2

W475 721 004 0

1396041

i = 1 : 1.5

MEEREGEL

VENTIEL

EMPTY

-LOAD V

A

LV

E

LAST

-LEER VENTIEL

V

A

LVE CHARGE-VIDE

V

A

LVOLA VUOTO-CARICO

V

A

LVULA V

ACIO-CARGA

p1 = > 8.5 bar

p4 = 8.0 bar

L = 140 mm

a = 15 ±2

G=11.0

L

p1

p2

p4

R600479

EXPLANATORY NOTES ON THE MAINTENANCE ACTIVITIES

3-26

©

200423

Inspection and adjustment

5

ΧΦ75 series

Checking and adjusting load-sensing leaf-
spring control valve
1.

Measure the weight plus load of the rear

axle(s).

2.

Check the attachment of the control lever

and its ease of operation.

3.

Check whether the correct valve and the

correct springs have been fitted (for

information, see the instruction plate).

4.

Check the length of the control lever (see "L"

on the instruction plate).

5.

Connect pressure gauge (4) to the test

connection close to connecting point

 on

the load-dependent control valve (input

pressure).

6.

Connect pressure gauge (2) to the test

connection on one of the brake cylinders

(service brake connection) of the rear axle.

7.

Make sure that the reservoir pressure is

higher than 8.5 bar throughout the testing

process.

8.

Depress the brake pedal until gauge (4)

indicates a reading of 8 bar.

9.

Read the brake pressure of the rear axle

from the pressure gauge (2) and check that

this value matches the one listed on the

instruction plate in the table under "delivery

pressure p2" to the rear axle.

1/4

4

2

2

R600562

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