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Checking brake booster - AR43.10-P-0325EW

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MODEL 212, 218 

Shown on model 212 

Fig 1: Checking Brake Booster
G09976631Courtesy of MERCEDES-BENZ USA
INSPECT 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
NOTES Brake fluid notes   AH42.50-P-0001-01A
1 Eliminate vacuum in BAS brake booster (A7/7) IMPORTANT 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 
SPECIAL TOOL Vacuum tester Figure
SPECIAL TOOL Test connection Figure
4 Connect pressure tester (051) with connection fitting to brake caliper NOTES Use the correct connection fitting (pitch, taper etc.), otherwise leakage and measurement errors will occur.  
TORQUE SPECIFICATION *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 IMPORTANT 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) IMPORTANT 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.
IMPORTANT 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 IMPORTANT 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
PNEUMATIC BRAKE BOOSTER TEST SPECIFICATIONS

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
FRONT AXLE BRAKE CALIPER

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
FRONT AXLE BRAKE CALIPER

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
FRONT AXLE BRAKE CALIPER

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
Fig 2: Identifying Vacuum Tester (201 589 13 21 00)
G09976632Courtesy of MERCEDES-BENZ USA
Fig 3: Identifying Test Connection (168 589 08 63 00)
G09976633Courtesy of MERCEDES-BENZ USA