Checking brake booster

AR43.10-S-0325A

Checking brake booster

10.2.97



Check

 Danger!

Risk of death caused by vehicle slipping or toppling off of the lifting platform.

Align vehicle between the columns of the hydraulic hoist and position the four support plates below the hoist support points specified by the vehicle manufacturer.

AS00.00-Z-0010-01A

 Danger!

Risk of poisoning from swallowing brake fluid. Risk of injury from brake fluid coming into contact with skin and eyes.

Pour brake fluid only into suitable and appropriately marked containers. Wear protective clothing and eye protection when handling brake fluid.

AS42.50-Z-0001-01A



Brake fluid notes

AH42.50-P-0001-01A

1

Connect vacuum tester (030) to brake booster (1)

AR43.10-S-0024-01A

2

Connect pressure tester (051) with connection fitting to brake caliper

 Pressure tester (single and dual-circuit hydraulic brake systems)

*WH58.30-Z-1012-15A

3

Mount pedal force meter (060) on the brake pedal (4)

 Pedal force meter

*WE58.40-Z-1003-19A

 Danger!

Risk of accident caused by vehicle starting off by itself when engine is running. Risk of injury caused by contusions and burns when working in engine during starting procedure

Secure vehicle to prevent it from moving.
Wear closed and snug-fitting work clothes.
Do not grasp hot or rotating parts.

AS00.00-Z-0005-01A

4.1

Checking brake booster

Only with engines 104, 111, 611

 Start engine and generate specified vacuum by opening the throttle and suddenly releasing the accelerator pedal

 If the specified vacuum is not generated, check the seal between the brake booster and stepped master brake cylinder, to do this:



Remove/install stepped tandem brake master cylinder

AR42.10-S-0310M

 Check vacuum line with rubber supports and check valve (2):



Check the check valve (2)

AR43.10-S-0023A

Brake pipe line pressure

*BE43.10-N-1003-01A

4.2

Checking brake booster

Only with engine 601

 Start engine and generate specified vacuum by opening the throttle and suddenly releasing the accelerator pedal

 If the specified vacuum is not generated, check the seal between the brake booster and stepped master brake cylinder, to do this:



Remove/install stepped tandem brake master cylinder

AR42.10-S-0310M

 Check vacuum line with rubber supports and check valve (2):



Check the check valve (2)

AR43.10-S-0023A

 Check vacuum pump



Check vacuum pump

AR43.05-S-1325A

Brake pipe line pressure

*BE43.10-N-1003-01A

5

Apply the specified force to the brake pedal (4) and read off the brake line pressure

 The measured value must be within the value range.

Brake pipe line pressure

*BE43.10-N-1003-01A

6

Detach pedal force meter (060) from brake pedal (4)

 Pedal force meter

*WE58.40-Z-1003-19A

7

Disconnect pressure tester (051) with connection fitting from brake caliper

 Pressure tester (single and dual-circuit hydraulic brake systems)

*WH58.30-Z-1012-15A

8

Disconnect vacuum tester (030) from brake booster (1)

AR43.10-S-0024-01A

9.1

Bleed brake system

Except with rear lowerable/raisable air suspension, code CL0,

Except brake system,antilock brake system ABS, code BB0

AR42.10-S-0010M

 Only bleed the brake caliper to which the pressure tester (051) was connected.

9.2

Bleed brake system

with rear lowerable/raisable air suspension, code CL0, with brake system, antilock brake system ABS, code BB0

AR42.10-S-0010-07A

 Only bleed the brake caliper to which the pressure tester (051) was connected.

Number

Designation

Model
638

BE43.10-N-1003-01A

Brake pipe line pressure

Intake manifold
vacuum

Force on brake pedal

50 N

bar

15

0.75...0.8 bar

100 N

bar

38

150 N

bar

60

200N

bar

82

250N

bar

100

Number

Designation

WH58.30-Z-1012-15A

Pressure tester (hydraulic single / dual circuit brake systems)

WE58.40-Z-1003-19A

Pedal force meter