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DAF CF65, CF75, CF85 Series . Manual - part 906

200423

2-9

Inspection and adjustment

BRAKE SYSTEM AND COMPONENTS

ΧΦ65/75/85 series

2.6 INSPECTION AND ADJUSTMENT, LOAD SENSING VALVE,

LEAF SUSPENSION

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.

Inspection/adjustment
1.

Measure the weight plus load of the rear
axle(s).

Check the attachment of the control lever
and its ease of operation.

Check whether the correct valve and the
correct springs have been fitted
(for information, see the instruction plate).

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

1.8

2.0

3.0

4.0

8.0

10.0

11.5

13.0

1.8

2.2

3.1

6.4

7.6

8.2

5.7

5.8

6.1

7.4

7.8

8.0

ASLAST G

AXLE LOAD

ACHSLAST

CHARGE SOUS ESSIEU

CARICO ASSE

CARGA EJE

x10

UITGESTUURDE DRUK p2

DELIVER

Y PRESSURE

AUSGESTEUER

TER DRUCK

PRESSION DELIVREE

PRESSIONE USCIT

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

LAST

-LEER VENTIEL

LVE CHARGE-VIDE

LVOLA VUOTO-CARICO

LVULA V

ACIO-CARGA

p1 = > 8.5 bar

p4 = 8.0 bar

L = 140 mm

a = 15 ±2

G=11.0

R600479

BRAKE SYSTEM AND COMPONENTS

2-10

200423

Inspection and adjustment

ΧΦ65/75/85 series

Check the length of the control lever
(see "L" on the instruction plate).

Connect a pressure gauge (4) to the test
connection near connection 1/4 on the load
sensing valve (input pressure).

Connect a pressure gauge (2) to the test
connection on one of the brake cylinders
(service brake connection) of the rear axle.

Make sure that the reservoir pressure is
higher than 8.5 bar throughout the testing
process.

Depress the brake pedal until pressure
gauge (4) indicates a value of 8 bar.

Read the brake pressure of the rear axle
from 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.

10. Correct, if necessary, the brake pressure by

moving the rubber sleeve (1) in relation to the
vertical connecting rod. On no account
change the length L of the (horizontal)
control lever.

11. Dismantle the ball coupling (2) and move

the control lever towards maximum load.
Check that the delivery pressure is now
allowed through (almost) without reduction.

Note:
The small socket head screw in the centre of
the valve must not be adjusted.

1/4

R600562

R600781

200423

2-11

Inspection and adjustment

BRAKE SYSTEM AND COMPONENTS

ΧΦ65/75/85 series

2.7 INSPECTION EMPTY/LOAD RELAY VALVE

Using a T-piece, connect a pressure gauge
to connecting point (41).

Connect a pressure gauge to the test
connection on one of the brake chambers
of the front axle.

Connect a pressure gauge to the test
connection on one of the brake chambers
of the rear axle.

Pressurise the system.

Testing when empty
1.

Set the load sensing valve to the empty
position.

Slowly depress the brake pedal.
The pressure on the front axle should rise
gradually, not in jumps.
The pressure on the front axle will rise less
quickly than that on connecting point (41).
(With an empty vehicle, the difference will be
greater than with a partially loaded vehicle).

R600904

R600905

BRAKE SYSTEM AND COMPONENTS

2-12

200423

Inspection and adjustment

ΧΦ65/75/85 series

Testing when fully loaded
1.

Set the load sensing valve to the full-load
position.

Slowly depress the brake pedal.
The pressure on the front axle should rise
gradually, not in jumps.
The pressure on the front axle will rise as
quickly (approx. 0.2 bar) as that on
connection point (41). It must be possible
to approximate the system pressure.

Inspection when faulty
1.

Disconnect the pipe to connecting point (42)
and plug off the pipe.

Repeat point 8.

Set the load sensing valve as specified.

Reconnect the pipes to points (41) and (42)
in the original manner.

Remove the pressure gauges.

Inspection, output pressure to the front axle
1.

Measure the rear axle load.

Check the load sensing valve setting.

Connect a pressure gauge to the test
connection for the load sensing valve
(input pressure) and a pressure gauge
to the test connection on the brake cylinder
of the front axle.

Make sure that the reservoir pressure
exceeds 6.5 bar.

Depress the brake pedal until the pressure
gauge on the test connection of the load
sensing valve reads 6 bar, and read off the
braking pressure on the pressure gauge
of the front axle.

Compare this value with the data in the table
attached to the door pillar.

0,1

0,25

R600906

0,1

0,5

1:2,7

1:1,5

41(bar)

2(bar)

R600745

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