DAF LF45, LF55 Series. Manual — part 453

©

200436

2-33

Description of components

OPERATION OF BRAKE COMPONENTS

ΛΦ45/55 series

6

3

2.18 DISC BRAKE CONSTRUCTION, WABCO MODEL

PAN 17 and PAN 19-1+ versions

Operation
Brakes

This disc brake operates using a pneumatic

brake cylinder or spring brake cylinder.

If the brake is applied, the brake cylinder push

rod presses against the eccentrically mounted

lever (1).

Via brake cylinder 2 and pressure plate 3, the

brake pad is pressed against the inside of the

brake disc (4).

Due to the reaction force at the eccentric, the

floating brake calliper (5) will also press the

opposite brake pad with the same force.

Adjusting
If the eccentrically mounted lever (6) is operated

by the push rod of the brake cylinder, the pin (7)

on the lever will rotate the adjuster (8) and the

pressure cylinder (9) in the outgoing stroke until

the play has been eliminated.

If the brake is no longer being operated, the

lever (6) will turn the adjuster (8) back in the

opposite direction. The spring (10) in the adjuster

will ensure that the pressure cylinder will hardly

rotate. The result is that a small total play of about

0.5 mm will remain between the brake pads and

brake disc.

Brake pad wear wires
Brake pad wear wires are fitted to the brake pads.

These wires are cut through when the brake

lining has been worn down to the minimum

thickness.

This is the signal for the VIC system to activate

the "brake pad wear" warning symbol on DIP-4.

R600573

R600574

1

3

5

4

2

R600579

9

7

8

6

10

OPERATION OF BRAKE COMPONENTS

2-34

©

200436

Description of components

3

ΛΦ45/55 series

6

PAN 19-2 version

Operation
Brakes

This disc brake operates using a pneumatic

brake cylinder or spring brake cylinder.

If the brake is applied, the brake cylinder push

rod presses against the eccentrically mounted

lever (1).

The brake pad is forced against the inside of the

brake disc via the brake piston (2) and the

pressure plate (3).

Due to the reaction force at the eccentric, the

floating brake calliper (4) will also press the

opposite brake pad with the same force.

Adjusting
This adjuster and the eccentric are equipped with

teeth (6) that engage each other.

If the play is too great, the adjuster (7) will be

rotated by these teeth the next time the brakes

are applied, so that the play will be reduced.

Under normal conditions, the adjuster will push

against the brake pad before rotation can take

place. However, if rotation does take place, it will

be absorbed by a slip coupling.

By removing one of the rubber caps (8) where the

automatic adjuster is located, a hexagon is

revealed. Using a ring spanner, the play can be

manually set by adjusting this hexagon.

Brake pad wear wires
Brake pad wear wires are fitted to the brake pads.

These wires are cut through when the brake

lining has been worn down to the minimum

thickness.

This is the signal for the VIC system to activate

the "brake pad wear" warning symbol on the

instrument panel.

R600578

3

4

1

2

R600577

6

7

8

5

©

200436

2-35

Description of components

OPERATION OF BRAKE COMPONENTS

ΛΦ45/55 series

6

3

2.19 DISC BRAKE CONSTRUCTION, KNORR MODEL

The disc brake construction consists of the brake

disc and the brake calliper. There are two

variants of this construction:

-

Knorr SB7000, recognisable by the divided

housing between the brake cylinder and the

brake pad holder.

-

Knorr SN7000, recognisable by the

undivided housing between the brake

cylinder and the brake pad holder.

The operation of the two variants is identical.

Only the reconditioning of the brake calliper is

different.

The Knorr SB7000 construction has been used

since the introduction of the LF 45/55 series. The

Knorr SN7000 construction is used in production

from week 41-2002 on all front axles and on air-

sprung rear axles (Class 3 vehicles). On leaf-

sprung rear axles the Knorr SB7000 construction

is still used. The operation of the two variants is

identical. Only overhauling and the parts of the

brake calliper differ.

Operation
Brakes

This disc brake operates using a pneumatic

brake cylinder or spring brake cylinder.

If the brake is applied, the brake cylinder push

rod presses against the eccentrically mounted

lever (1).

Via the bridge (2) and the threaded bushes (3),

the brake pad is pressed against the brake

disc (4) at two points on the inside.

Due to the reaction force at the eccentric, the

floating brake calliper (5) will also press the

opposite brake pad with the same force.

R600707

SB7000

SN7000

OPERATION OF BRAKE COMPONENTS

2-36

©

200436

Description of components

3

ΛΦ45/55 series

6

Adjusting
One of the two threaded bushes (3) is equipped

with the mechanics for automatic adjustment of

the play between the brake pads and brake disc.

This adjuster and the eccentric are equipped with

teeth (6) that engage each other.

If the play is too great, the adjuster (8) will be

rotated by these teeth the next time the brakes

are applied, so that the play will be reduced.

Under normal conditions, the adjuster will push

against the brake pad before rotation can take

place. However, if rotation does take place, it will

be absorbed by a slip coupling.

The rotation of the adjuster is transferred by

means of a chain (7) to the other adjuster.

By removing a rubber cap (9) where the

automatic adjuster is located, a hexagon is

revealed. Using a ring spanner, the play can be

manually set by adjusting this hexagon.

4

5

1

3

2

R600486

R600487

3

7

6

8

3

9