Remove/install brake booster

AR43.10-P-0350MFA

Remove/install brake booster

06.03.2020

Model

118, 177, 247

Modification notes

15.01.2020

Document completely revised.

Shown on model 177.0 except code ME08 (Hybrid drive 75-84 KW VARIANT (INCLUDING PLUGIN))

2

Battery carrier

3

Firewall support

Shown on model 177.0 except code ME08 (Hybrid drive 75-84 KW VARIANT (INCLUDING PLUGIN))

7

Brake lines

Shown on model 177.0 except code ME08 (Hybrid drive 75-84 KW VARIANT (INCLUDING PLUGIN))

1

Brake booster

12

Master brake cylinder with brake fluid reservoir

7

Brake lines

13

Vacuum line

11

Electrical connector

16

Electrical connector

Shown on model 177.0

14

Screw

15

Nut

 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 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

Topical note

Notes on self-locking nuts and bolts

AH00.00-N-0001-01A

Topical note

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

Topical note

Brake fluid notes

AH42.50-P-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

Notes on safety-relevant components

AH00.00-Z-0019-01A

 

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

Remove battery carrier (2) with firewall support (3).

AR54.10-P-0028MFA

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

Remove engine compartment prefuse box (F150/3).

AR54.15-P-1330MFA

12

Release and disconnect electrical connector (11) from brake vacuum sensor (B150).

Topical note

Information on preventing damage to electronic components due to electrostatic discharge

AH54.00-P-0001-01A

13

Cover painted surfaces in the repair area.


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).


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.

 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

 Retaining screw, brake line to master brake cylinder

*BA42.10-P-1002-04Q

 Box wrench bit

*140589000300

 Record plug

*129589009100

16

Move brake lines (7) far enough into holders so that the installation space of the brake booster (1) is free.


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: 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.

 Record plug

*129589009100

20

Release and disconnect electrical connection (16).

21

Remove electric line from brake booster (1).

 Clip remover

*452589016300

22

Remove lower trim for instrument panel on driver's side.

AR68.10-P-1501MFA

23

Unscrew screw (14).

 Bolt, brake pedal brake booster retaining bolt

*BA43.10-P-1002-01L

24

Remove nuts (15).

 Nut, brake booster to front end

*BA43.10-P-1001-01L

25

Remove brake booster (1) forward.


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).

If the brake booster (1) is to be replaced.

AR42.10-P-0300MFA

27

Remove brake vacuum sensor (B150) from brake booster (1).

If the brake booster (1) is to be replaced.

28

Install in the reverse order.



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.



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

Repair materials

Number

Designation

Order number

BR00.45-Z-1028-04A

Assembly cleaner

A 000 986 56 01