Check/adjust automatic load-dependent brake (ALB)

AR42.80-G-0050F

Check/adjust automatic load-dependent brake (ALB)

5.8.15

Model

437.46 with rear axle 747.224 with front axle 737.224

with 4-channel ABS

1

ALB plate (automatic load-dependent brake)

2

Control linkage

3

Actuating lever

4

ALB controller

5

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

7

Test connection (brake pressure regulated, rear axle)

 Danger !

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 of vehicle in ready-to-drive condition by weighing, and note down

 Test balance

*385589052100

2

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

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

3

Check that control linkage (2) and operating lever (3) can move easily and that joints are play-free

If there are problems:



Repair control linkage (2) and operating lever (3).

4

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

In the event of a deviation:



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

5

Connect pressure gauge to test connections (5, 7)

6

Pressurize compressed-air system up to cutoff 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 present at test connection (5), and hold brake pedal in position

 The pressure gauge of the controlled circuit must come to a standstill within the specified pressure range.
Permissible values are given in the ALB settings diagram on the ALB plate (1) referred to the rear axle load. A deviation of  0.4 bar is permissible.

If pressure deviates significantly:



Adjust ALB controller (4).

Adjust

8

Slacken lock nuts on control linkage (2)

 Brake must be disengaged.

9

Adjust control linkage (2)

 Obtain assistance from a second person.
Adjust the control linkage (2) until the required pressure is indicated on the pressure gauge.
Pressure too low: Extend control linkage (2).
Pressure too high: Shorten control linkage (2).

10

Tighten lock nuts on control linkage (2)

11

Recheck ALB setting

If there are problems:



Repeat the adjustment procedure.

12

Turn off engine

13

Detach pressure gauge

14

Check brake system for leaks and proper function