Check/adjust automatic load-dependent brake (ALB)

AR42.80-G-0050BB

Check/adjust automatic load-dependent brake (ALB)

04.02.2020

Model

405.102/122 ## as of 197880

with 4-channel ABS

Model

405.103/123/200/201/220/221

with 4-channel ABS

Model

437.43# ## up to 262508 with rear axle 747.222 with front axle 737.222

with 4-channel ABS

Illustrated on model 405

1

ALB plate (automatic load-dependent brake)

Illustrated on model 405

2

Control linkage

3

Actuating lever

4

ALB controller

5

Test connection (brake pressure uncontrolled, upstream of ALB controller (4))

Shown on model 405.102/122/200/220

6

Test connection (brake pressure uncontrolled, upstream of load/no-load valve)

Shown on model 405.103/123/201/221

5

Test connection (brake pressure uncontrolled, upstream of ALB controller (4))

6

Test connection (brake pressure uncontrolled, upstream of load/no-load valve)

Shown on model 437

7

Test connection (brake pressure regulated, rear axle)

8

Test connection (brake pressure controlled, front axle)

 Warning

Risk of accident from vehicle starting off by itself when engine running. Risk of injury (bruises and burns) resulting from working on the engine while it is being started or when it is running.

Secure vehicle to prevent it from starting off by itself. Wear closed and snug-fitting work clothes. Do not touch hot or rotating parts.

AS00.00-Z-0005-01A



Check

1

Determine rear axle load on ready to drive vehicle by weighing it, then note it down.

 Test balance

*385589052100

2

Note down test values for control linkage (2), operating lever (3) and brake pressures specified on ALB plate (1).

 The ALB plate (1) is located on the inside of the left door.

3

Check control linkage (2) and operating lever (3) for ease of movement and free play of joints.

If a problem is found,



repair the control linkage (2) or the operating lever (3).

4

Check length of control linkage (2) and operating lever (3).

 For data, refer to ALB plate (1).

If a problem is found,



Adjust length of control linkage (2) and operating lever (3).

5

Connect manometer to test connections (5, 6, 7, 8).

 Model 437.43 with code F10 (Protected cab) with 4-channel ABS
The test connection (6) is no longer present.

6

Start engine and fill compressed air system up to shutoff pressure.

 Before fully depressing the brake pedal each time, the compressed-air system must be filled until the shutoff pressure is reached.

7

Fully depress brake pedal until a pressure of 8.1 bar is applied at the test connection (5) and hold brake pedal in position.

 The controlled circuit manometer must come to a stop within the specified pressure range.
For permissible values, see diagram for ALB setting on ALB plate (1) relative to rear axle load.
For permissible deviation, see ALB plate (1).

If a problem is found,



adjust automatic load-dependent brake (ALB).

Adjust

8

Release counternuts on control linkage (2).

 Brake must be disengaged.

9

Adjust control linkage (2).

 Helper required.
Adjust control linkage (2) so that the required pressure is shown on the manometer.
Pressure too low: Lengthen control linkage (2).
Pressure too high: Shorten control linkage (2).

10

Tighten counternuts on control linkage (2).

11

Check setting again.

If problems occur,



Repeat the adjustment procedure.

12

Switch off engine.

13

Detach pressure gauge.

14

Check brake system for leak tightness and proper operation.