Checking brake booster

AR43.10-P-0325EW

Checking brake booster

6.9.11



Checking

 Danger!

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

Only pour brake fluid 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

Eliminate vacuum in BAS brake booster (A7/7)

 To do this, press the brake pedal several times with the engine switched off.

2

Open engine hood

Model 218

Model 212

AR88.40-P-1000EW

3

Connect vacuum tester (030) with test connection (031) to BAS brake booster (A7/7)

AR43.10-P-0024-01V

Pneumatic brake booster test specifications

*BE43.10-P-1001-01F

Pneumatic brake booster test specifications

*BE43.10-P-1002-01F

 Vacuum tester

*201589132100

 Test connection

*168589086300

4

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

 Use the correct connection fitting (pitch, taper etc.), otherwise leakage and measurement errors will occur.



*BA42.10-P-1003-10J

5

Connect pedal force measuring instrument (060) at brake pedal

6

Start engine and by opening the throttle produce a vacuum of 0.75 to 0.8 bar

 If this vacuum is not reached or it drops immediately, the seal between the BAS brake booster (A7/7) and master brake cylinder may be damaged or the check valve (17) in the vacuum line (8) may be defective:

Check non-return valve.

AR43.10-P-0023EW

Remove/install master brake cylinder, replace seal.

AR42.10-P-0300EW

7

Apply the specified force to the brake pedal and read off the line pressure on the pressure tester (051)

 In order to cover measurement errors (incorrect force on the brake pedal, incorrect vacuum) and scatter of the measuring devices, a tolerance of 10 bar on the specified value is permissible.

 The measured value must be within the value range.

Brake pipe line pressure

*BE43.10-P-1003-01F

8

Detach vacuum tester (030) with test connection (031) from BAS brake booster (A7/7)

9

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

10

Remove pedal force meter (060)

11

Bleed brake system

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

AR42.10-P-0010EW

 Danger!

Risk of accident caused by vehicle starting off by itself when engine is running. Risk of injury caused by contusions and burns during starting procedure or when working near the engine as it is running

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

AS00.00-Z-0005-01A

12

Check brake system for leaks

AR42.10-P-0100-01V

Number

Designation

Model 212

Model 218

BE43.10-P-1001-01F

Brake booster
dia.

–

mm

203/229

203/229

–

inches

8/9

8/9

BE43.10-P-1002-01F

Boost factor

7

7

BE43.10-P-1003-01F

Brake pipeline
pressure

Intake manifold
vacuum
0.75...0.8 bar

Force on brake pedal

50 N

bar

17.7...24.7

17.7...24.7

100 N

bar

-

-

150n

bar

62...78

62...78

200n

bar

83...102

83...102

250n

bar

105...122

105...122

Number

Designation

Model
212 except
model
212.074/077/274/277

Model
212.074/077/
274/277 without code B07

BA42.10-P-1003-10J

Bleed screw to brake caliper

Nm

14

14

Number

Designation

Model
212.074/077/
274/277 with code B07

Model
218
except model
218.374

BA42.10-P-1003-10J

Bleed screw to brake caliper

Nm

14

14

Number

Designation

Model
218.374 without code B07

Model
218.374 with code B07

BA42.10-P-1003-10J

Bleed screw to brake caliper

Nm

14

14