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Home >> Mercedes Benz >> 2021 >> A35 AMG >> Repair and Diagnosis >> Brakes >> Mechanical - Hydraulic >> Brakes - Pneumatic System - 177 Chassis >> Testing & Repair >> Remove/Install Brake Booster - AR43.10-P-0350MFA

Remove/Install Brake Booster - AR43.10-P-0350MFA

Model 118, 177, 247 

MODIFICATION NOTES

09.07.2021 Remove refrigerant lines from expansion valve. Operation step 9.2.  
09.07.2021 Remove right engine mount. Operation step 11.2.  
G15491914Courtesy of MERCEDES-BENZ USA

Shown on model 177.0## 1# except code ME08 (Hybrid drive 75-84 KW VARIANT (INCLUDING PLUG-IN)) 

G15491915Courtesy of MERCEDES-BENZ USA

Shown on model 177.0## 1# except code ME08 (Hybrid drive 75-84 KW VARIANT (INCLUDING PLUG-IN)) 

Fig 1: Brake Booster Components Location - Model 177 (Shown On Model 177.0## 1# Except Code ME08)
G15491916Courtesy of MERCEDES-BENZ USA

Shown on model 177.0## 1# except code ME08 (Hybrid drive 75-84 KW VARIANT (INCLUDING PLUG-IN)) 

Shown on model 177.0## 1# 

G15491917Courtesy of MERCEDES-BENZ USA
DANGER Risk of fire  due to ignition of R1234yf refrigerant on hot components. Risk of poisoning  caused by inhaling overheated refrigerant vapors. Risk of injury  to skin and eyes caused by contact with escaped R1234yf refrigerant and when working on pressurized parts. Risk of explosion  due to formation of ignitable refrigerant/air mixtures Never perform welding work on or near a closed air conditioning system. No smoking or open flames. Wear safety glasses and protective gloves. Work only in well ventilated rooms. Carry out repair work on the air conditioning system circuit only after the system has been evacuated. AS83.00-Z-0007-01A
DANGER Risk of death  when working on component parts and systems with U >= 30 V alternating voltage (AC) or U >= 60 V direct voltage (DC) Do not touch damaged or defective live component parts and lines or non-insulated electrical connections and lines. Model 177, 247 with engine 282
with code ME08 (Hybrid drive 75-84 kW VARIANT (INCLUDING PLUGIN))
AS00.00-Z-0035-01A
DANGER Risk of accident  when commissioning the vehicle due to a lack of braking effect when the service brake is operated for the first time after repair work. Before starting the engine, actuate brake pedal several times until pressure is built up and maintained in the brake system. AS42.50-Z-0002-01A
WARNING Risk of poisoning  caused by inhaling overheated refrigerant vapors from an air conditioning system containing R134a. Risk of injury  to skin and eyes caused by contact with liquid R134a refrigerant and when working on pressurized parts Never perform welding work on or near a closed air conditioning system. No smoking or open flames. Wear safety glasses and protective gloves. Work only in well ventilated rooms. Carry out repair work on the air conditioning system circuit only after the system has been evacuated. AS83.00-Z-0006-01A
WARNING Risk of injury.  Skin or eye injuries may result when handling hot or glowing objects. Wear protective gloves, protective clothing and safety glasses, if necessary. AS00.00-Z-0002-01A
CAUTION Risk of injury  caused by scraping or cutting body parts on sharp vehicle parts Always wear protective gloves when working on or near sharp and non-deburred vehicle parts.
Deburr repair panels.
AS00.00-Z-0017-01A
CAUTION Risk of poisoning  from swallowing brake fluid. Risk of injury  from skin and eye contact with brake fluid 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
Notice  Information on preventing damage to electronic components due to electrostatic discharge   AH54.00-P-0001-01A
Notice  Notes on avoiding damage through contamination and foreign objects   AH00.00-P-5000-01A
Notice  Notes on self-locking nuts and bolts   AH00.00-P-0001-01KOA
Notice  General information on vehicles with high-voltage on-board electrical system and/or lithium-ion battery and/or gaseous-fuel drive system as well as personal protective equipment Model 177, 247 with engine 282
with code ME08 (Hybrid drive 75-84 kW VARIANT (INCLUDING PLUGIN))
AH00.00-Z-0300-01A
Notice  Brake fluid notes   AH42.50-P-0001-01A
Notice  Notes on repairs to brake system   AH42.00-P-0003-01A
Notice  Notes on externally invisible brake fluid loss   AH42.10-P-9406-02A
  Notes on safety-relevant components   AH00.00-Z-0019-01A
REMOVINGINSTALLING Remove/install     
1 Reduce vacuum in brake booster (1) by depressing the brake pedal several times.    
2 Thoroughly clean area around brake fluid reservoir. Assembly cleaner *BR00.45-Z-1028-04A 
3 Remove cap.    
4 Remove sieve from brake fluid reservoir.    
5 Extract brake fluid from brake fluid reservoir.    
6 Install sieve in brake fluid reservoir.    
7 Attach cap.    
8 Remove brake lines (7) from hydraulic unit.   AR42.40-P-0816MFA
9.1 Remove battery carrier (2) with firewall support (3). Model 118.### 1#, 177.### 1#, 247.### 1#  
      AR54.10-P-0028MFA
9.2 Remove refrigerant lines from expansion valve. Model 118.### 2#, 177.### 2#, 247.### 2#  
      AR83.30-P-5520MFA
10 Remove holders for power electronics. Model 177, 247 with engine 282
with code ME08 (Hybrid drive 75-84 kW VARIANT (INCLUDING PLUGIN))
 
      AR08.00-P-0005MFH
11.1 Remove engine compartment pre-fuse box (F150/3). Model 118.### 1#, 177.### 1#, 247.### 1#  
      AR54.15-P-1330MFA
11.2 Remove right engine mount. Model 118.### 2#, 177.### 2#, 247.### 2#  
    Model 118.### 2#, 177.### 2#, 247.### 2# with engine 139 AR22.10-P-1102MFG
    Model 118.### 2#, 177.### 2#, 247.### 2# with engine 260, 282 AR22.10-P-1102MFD
    Model 118.### 2#, 177.### 2#, 247.### 2# with engine 608 AR22.10-P-1102MFE
    Model 118.### 2#, 177.### 2#, 247.### 2# with engine 654 AR22.10-P-1102MFF
12 Release and disconnect electrical connector (11) from brake vacuum sensor (B150).    
Notice  Information on preventing damage to electronic components due to electrostatic discharge   AH54.00-P-0001-01A
13 Cover painted surfaces in the repair area. NOTES
Protect painted surfaces from brake fluid. Otherwise damage will be caused by escaping brake fluid.
 
14 Clean master brake cylinder in area of connections of brake lines (7). NOTES
Thoroughly clean area around connecting points before opening the brake system.
Otherwise minute dirt particles in the hydraulic components result in malfunctions and total failure of the brake system.
IMPORTANT Only use clean, lint free rags and cleaner free of mineral oil.
Do not use any compressed air for cleaning when the brake system is open.
 
    Assembly cleaner *BR00.45-Z-1028-04A 
15 Remove brake lines (7) from master brake cylinder and seal connections with suitable stop plugs.    
  Note on calculation of tightening torque when using insertion or socket tools with various effective lengths   AH00.00-P-0015-01CW
    TORQUE SPECIFICATION Retaining screw, brake line to master brake cylinder *BA42.10-P-1002-04Q 
    SPECIAL TOOL Box wrench bit Fig 3
    SPECIAL TOOL Record plug Fig 2
16 Move brake lines (7) far enough into holders so that the installation space of the brake booster (1) is free. NOTES
Do not deform the brake lines (7).
Otherwise failure can occur to the brake system.
 
17 Detach vacuum line (13) from brake booster (1). INSTALLATION IMPORTANT Ensure that seal is correctly seated.  
18 Check seal of vacuum line (13) in brake booster (1) for damage. If damage is visible,

Replace seal of vacuum line (13) in brake booster (1).
 
19 Seal opening of vacuum line (13) and brake booster (1) using suitable stop plugs. SPECIAL TOOL Record plug Fig 2
20 Release and disconnect electrical connection (16).    
21 Remove electric line from brake booster (1). SPECIAL TOOL Clip remover Fig 4
22 Remove lower trim for instrument panel on driver's side.   AR68.10-P-1501MFA
23 Unscrew screw (14). TORQUE SPECIFICATION Bolt, brake pedal brake booster retaining bolt *BA43.10-P-1002-01L 
24 Remove nuts (15). TORQUE SPECIFICATION Nut, brake booster to front end *BA43.10-P-1001-01L 
25 Remove brake booster (1) forward. NOTES
Do not damage boot when removing/installing brake booster (1).
Otherwise the brake booster (1) will fail.
 
26 Detach master brake cylinder with brake fluid reservoir (12) from brake booster (1). When replacing brake booster (1).  
      AR42.10-P-0300MFA
27 Remove brake vacuum sensor (B150) from brake booster (1). When replacing brake booster (1).  
28 Install in the reverse order.    
INSPECT Check     
DANGER Risk of death  caused by limbs being caught or crushed by rotating parts when performing tests on the brake test stand Never leave the vehicle unattended on the rollers except in an emergency. Ensure that no one is under the vehicle or near rotating parts during testing. In case of emergency, use the EMERGENCY OFF switch to shut down test stand. AS42.00-Z-0001-01A
29 Perform brake test on roller brake test stand.    
REFER TO MAINTENANCE Brake test   AP42.00-P-4290BA
BRAKE LINES

Number Designation Model 118 Model 177
BA42.10-P-1002-04Q Retaining screw, brake line to master brake cylinder Nm 16 16
BRAKE LINES

Number Designation Model 247
BA42.10-P-1002-04Q Retaining screw, brake line to master brake cylinder Nm 16
PNEUMATIC BRAKE BOOSTER

Number Designation Model 118 Model 177, 243, 247
BA43.10-P-1001-01L Nut, brake booster to front end M8 Nm 22 22
PNEUMATIC BRAKE BOOSTER

Number Designation Model 118 Model 177, 243, 247
BA43.10-P-1002-01L Bolt, brake pedal brake booster retaining bolt Nm 22 22
Fig 2: Identifying Record Plug (129 589 00 91 00)
G11065549Courtesy of MERCEDES-BENZ USA
Fig 3: Identifying Box Wrench Bit (140 589 00 03 00)
G13668668Courtesy of MERCEDES-BENZ USA
Fig 4: Identifying Clip Remover (452 589 01 63 00)
G11129172Courtesy of MERCEDES-BENZ USA
REPAIR MATERIALS

Number Designation Order number
BR00.45-Z-1028-04A Assembly cleaner A 000 986 56 01