Remove/install master brake cylinder

AR42.10-S-0300E

Remove/install master brake cylinder

09.03.2020

Model

447, 448

Modification notes

16.12.2019

Work procedure revised

The whole document

16.12.2019

Method adapted

Step 4

Shown on model 447 with engine 622

1

Master brake cylinder

4

Supply line

7

Retaining screws

2

Brake fluid reservoir

5

Expansion rivet

8

Nut

3

Electrical connector

6

Retaining screws

9

Sealing ring

 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 447 with engine 780

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

 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

Information on preventing damage to electronic components due to electrostatic discharge

AH54.00-P-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 447 with engine 780

AH00.00-Z-0300-01A

Topical note

Notes on externally invisible brake fluid loss

AH42.10-P-9406-02A

Topical note

Brake fluid notes

AH42.50-P-0001-01A

Topical note

Notes on repairs to brake system

AH42.00-P-0003-01A

Note on calculation of tightening torque when using insertion or socket tools with various effective lengths

AH00.00-P-0015-01CW

Notes on inspecting corrosion on brake lines

AH42.50-Z-0002-01A

 

Remove/install

1

Switch off ignition and store transmitter key outside of transmission range (min. 2  m).

2

Remove vacuum in brake booster.

 To do this, operate brake pedal several times.

3

Remove intake manifold pressure sensor.

Model 447 with engine 654.9

AR07.04-S-0102E

4

Suction off brake fluid from brake fluid reservoir (2) and then reseal brake fluid reservoir (2).

 Commercially available devices/tools
Extraction bellows

5

Detach feed line (4) of clutch master cylinder from brake fluid reservoir (2).

Model 447 with transmission 700.7, 710.5, 711.6

 Catch escaping brake fluid with a suitable rag and seal openings.

 Record plug

*129589009100

6

Disconnect electrical connector (3).

7

Remove expansion rivet (5).

 Installation: Check expansion rivet (5) for damage.

If damage is present,



replace expansion rivet (5).

8

Detach brake fluid reservoir (2) from air/water duct and swivel out of working area.

9

Unscrew retaining screws (6) and remove brake lines from master brake cylinder (1).

 Catch escaping brake fluid using a suitable rag and seal openings.
Different retaining screws (6) are installed depending on the vehicle version.

 Retaining screw, brake line to master brake cylinder

*BA42.10-N-1004-04D

 Box wrench bit

*000589750300

 Box wrench

*000589760300

 Box wrench bit

*140589000300

 Record plug

*129589009100

10

Loosen retaining screws (7) of brake lines on hydraulic unit.

 Only loosen brake lines enough for the master brake cylinder (1) to be guided past the brake lines.
Different retaining screws (7) are installed depending on the vehicle version.

 Retaining screw, brake line to hydraulic unit

*BA42.10-N-1003-04D

 Box wrench bit

*000589750300

 Box wrench

*000589760300

 Box wrench bit

*140589000300

11

Detach nuts (8) and remove master brake cylinder (1) with brake fluid reservoir (2).

 Installation: Replace the sealing ring (9) on the master brake cylinder (1).

 Nut, brake master cylinder to brake booster

*BA42.10-N-1001-05E

 Assembly tool

*000589936300

12

Detach brake fluid reservoir (2) from master brake cylinder (1).

When replacing the master brake cylinder (1).

13

Install in the reverse order.

14

Bleed brake system.

AR42.10-S-0010E



Check

 Warning

Risk of accident from vehicle starting off by itself when engine running. Risk of injury (bruises and burns) resulting from working on the engine while it is being started or when it is running.

Secure vehicle to prevent it from starting off by itself. Wear closed and snug-fitting work clothes. Do not touch hot or rotating parts.Model 447 with engine 274, 622, 651, 654
Model 448

AS00.00-Z-0005-01A

15

Check brake system in area of master brake cylinder (1), hydraulic unit and brake fluid reservoir (2) for leak tightness.

AR42.10-S-0100-01E

 Master brake cylinder

Number

Designation

Model 447, 448

BA42.10-N-1001-05E

Nut, brake master cylinder to brake booster

Nm

23

 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