DAF LF45, LF55 Series. Manual — part 647

©

200515

3-17

Inspection and adjustment

EXPLANATORY NOTES ON THE MAINTENANCE ACTIVITIES

ΛΦ45/55 series

5

3.24 CHECKING THE BRAKE PAD THICKNESS AND BRAKE DISC

Version: Knorr SB 7000
1.

Check whether guide bush (4) protrudes

from guide sleeve (6) (C).

If the guide bush (4) is level with the guide

sleeve (6) (see detail A) the brake pad and

brake disc thicknesses should be checked.

C

1

4

6

R600481

A

EXPLANATORY NOTES ON THE MAINTENANCE ACTIVITIES

3-18

©

200515

Inspection and adjustment

5

ΛΦ45/55 series

Version: Knorr SN 7000
1.

Check the transition between the ribbed part

of the rubber cover and the smooth part (A).

If the smooth part is rolled inwards, the brake

pad and brake disc thicknesses must be

checked.

Version: Wabco
1.

There is no wear indicator in this version.

The brake pad thickness must be inspected

by using a mirror and a lamp, if necessary.

A

A

A

R600730

©

200515

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Inspection and adjustment

EXPLANATORY NOTES ON THE MAINTENANCE ACTIVITIES

ΛΦ45/55 series

5

3.25 INSPECTION AND ADJUSTMENT, LOAD SENSING VALVE, AIR

SUSPENSION

Explanatory notes on instruction plate

The information contained on the plate relates to

the axle loads, the output pressures and bellows

pressures, in accordance with the order of axles

beneath the vehicle.

"1" refers to the (first) front axle, "2" to the

following axle, etc.

In the entire column, a reading of 6 bar has been

filled in under "1".

If the vehicle is equipped with an empty/load

valve, a pressure ratio is entered in the box under

the valve illustration, 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.

Check that the correct valve has been fitted

(see instruction plate).

2.

Connect pressure gauge (4) to the test

connection close to connecting point 1/4 on

the load sensing valve (input pressure).

3.

Connect 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 6.5 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 the pressure

gauge (4) indicates a pressure of 6 bar.

R6 00 548

43

1/4

4

2

2

R600473

1

41 42

r

s

EXPLANATORY NOTES ON THE MAINTENANCE ACTIVITIES

3-20

©

200515

Inspection and adjustment

5

ΛΦ45/55 series

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 "output

pressure p2" to the rear axle.

9.

If the measured value is not correct,

depressurise connection (43) and, using a

special slotted-nut spanner, special tool

(DAF no. 1329464), turn the adjusting

nut (s):

-

brake pressure too high: unscrew the

adjusting nut

-

brake 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 brake pressure value is

within the tolerance limits.

11. Set the simulated bellows pressure to its

second highest value, as indicated on the

instruction plate.

12. Depress the brake pedal until the pressure

gauge (4) indicates a pressure of 6 bar.

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

brake 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

adjusting bolt (r) using a Torx screwdriver:

-

brake pressure too high: screw in the

adjusting bolt

-

brake 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.

R600478

43

1/4

4

2

2

R600473

1

41 42

r

s