Remove/install brake booster

AR43.10-S-0350E

Remove/install brake booster

06.03.2020

Model

447 with engine 622

Model

447 with engine 651

Model

447, 448 with engine 274

Modification notes

10.10.2019

Work procedure revised.

The whole document

Shown on model 447 with engine 651

1

Brake lines

3

Nut

6

Screw

2.1

Refrigerant line

4

Nuts

7

Vacuum line

2.2

Refrigerant line

5

Refrigerant line

Shown on model 448 with engine 274

3

Nut

4

Nuts

5

Refrigerant line

6

Screw

7

Vacuum line

12

Refrigerant line

Shown on model 447 with engine 651

8

Thrust rod

9

Cotter pin

10

Nuts

11

Brake booster

 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 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

 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

Topical note

Notes on repairs to brake system

AH42.00-P-0003-01A

Topical note

Notes on externally invisible brake fluid loss

AH42.10-P-9406-02A

Topical note

Notes on avoiding damage through contamination and foreign objects

AH00.00-P-5000-01A

Topical note

Protect air conditioning circuit and components from moisture when carrying out repair work

AH83.30-N-0005-01A

Topical note

Brake fluid notes

AH42.50-P-0001-01A

Notes on handling refrigerant R134a

AH83.30-N-0003-01A

Notes on handling refrigerant R1234yf

AH83.30-P-0003-02A

 

Remove/install

1

Reduce vacuum in brake booster (11) by depressing brake pedal several times in succession.

2

Discharge air conditioning system.

Model 447 with code HH4 (THERMOTRONIC automatic climate control) with code HX1 (Refrigerant R-1234yf) Model 447 with code HH9 (TEMPMATIC semi-automatically controlled air conditioning) with code HX1 (Refrigerant R-1234yf) Model 447 with code HX1 (Refrigerant R-1234yf) with code HZ7 (TEMPMATIC semi-automatically controlled air conditioning in rear passenger compartment)

AR83.30-S-1760EF

Model 447 with code HH4 (THERMOTRONIC automatic climate control) except code HX1 (Refrigerant R-1234yf) Model 447 with code HH9 (TEMPMATIC semi-automatically controlled air conditioning) except code HX1 (Refrigerant R-1234yf) Model 447 with code HZ7 (TEMPMATIC semi-automatically controlled air conditioning in rear passenger compartment) except code HX1 (Refrigerant R-1234yf) Model 448

AR83.30-S-1760E



Clean

3

Clean area surrounding cap on brake fluid reservoir and connections of brake lines (1) on master brake cylinder and on hydraulic unit.


Before opening the brake system, it must be ensured that the area around the connecting points has been cleaned completely.
Otherwise minute particles of dirt in the hydraulic components can result in malfunctions and total failure of the brake system.

 Use clean, lint-free rag only.

 Do not use any compressed air for cleaning when the brake system is open.

Assembly cleaner

*BR00.45-Z-1028-04A

4

Remove cap from brake fluid reservoir and take sieve out of brake fluid reservoir.

5

Extract brake fluid from brake fluid reservoir.

 Commercially available devices/tools
Extraction bellows

6

Remove air/water duct.

AR83.25-S-1410E

7

Remove engine cover.

Model 447 with engine 651

AR01.10-S-2405E

8.1

Remove brake lines (1).

Model 447.### 1#, model 448

 Seal connections.

 Retaining screw, brake line to hydraulic unit

*BA42.10-N-1003-04D

 Retaining screw, brake line to master brake cylinder

*BA42.10-N-1004-04D

 Box wrench bit

*000589750300

 Record plug

*129589009100

8.2

Remove brake lines (1) from master brake cylinder.

Model 447.### 2#

 Seal connections.

 Retaining screw, brake line to master brake cylinder

*BA42.10-N-1004-04D

 Box wrench bit

*000589750300

 Record plug

*129589009100

9

Remove nuts(4).

10

Remove refrigerant lines (2.1, 2.2) or refrigerant line (12).

Model 447.### 1# with code HH4 (THERMOTRONIC automatic climate control), model 447.### 1# with code HH9 (TEMPMATIC semi-automatically controlled air conditioning), model 448



Compressor oils (specification 362.0)

BB00.40-P-0362-00A

 For this purpose, remove nut (3). Seal connections.

 Installation: Replace sealing rings and moisten with compressor oil.

 Nut, refrigerant line to expansion valve

*BA83.30-N-1001-01A

 Record plug

*129589009100

11

Remove refrigerant line (5).

Model 447.### 1# with code HH4 (THERMOTRONIC automatic climate control) Model 447.### 1# with code HH9 (TEMPMATIC semi-automatically controlled air conditioning) Model 448



Compressor oils (specification 362.0)

BB00.40-P-0362-00A

 To do this, remove bolt (6). Seal connections.

 Installation: Replace sealing rings and moisten with compressor oil.

 Record plug

*129589009100

12

Remove refrigerant line (2.2) from longitudinal member.

Model 447.### 1# with code HH4 (THERMOTRONIC automatic climate control) Model 447.### 1# with code HH9 (TEMPMATIC semi-automatically controlled air conditioning)

 To do this, remove the holder.

13

Remove vacuum line (7).

 Installation: Check seal for vacuum line (7) on brake booster (11) for damage and leak tightness.

If seal is damaged or no longer seals correctly,



Replace seal.

14

Remove vacuum reservoir.

Model 447.### 1# with engine 651

AR07.09-S-0001E

15

Remove steering column tube.

AR46.10-S-0400E

16

Remove push rod (8).

 To do so, remove cotter pin (9).

17

Remove nuts (10).

 Nut, brake booster to firewall

*BA43.10-N-1001-01C

18

Move brake booster (11) forward and remove.

 Installation: Replace seal between brake booster (1) and firewall.

19

Transfer master brake cylinder.

If brake booster (11) is to be replaced.

AR42.10-S-0300E

20

Install in the reverse order.

21

Bleed brake system.

AR42.10-S-0010E



Check

22

Perform brake test.



Brake test

AP42.00-S-4290E

 Brake lines, brake hoses

Number

Designation

Model 447, 448

BA42.10-N-1003-04D

Retaining screw, brake line to hydraulic unit

Nm

14

 Brake lines, brake hoses

Number

Designation

Model 447, 448

BA42.10-N-1004-04D

Retaining screw, brake line to master brake cylinder

Nm

14

 Brake booster

Number

Designation

Model 447, 448

BA43.10-N-1001-01C

Nut, brake booster to firewall

Nm

20

 Air conditioning

Number

Designation

Model 447 with engine 622

Model 447 with engine 274, 651
Model 448 with engine 274

BA83.30-N-1001-01A

Nut, refrigerant line to expansion valve

Nm

8

8

Repair materials

Number

Designation

Order number

BR00.45-Z-1028-04A

Assembly cleaner

A 000 986 56 01