Audi A6 2005 - Electrics Instruction manual

Workshop Manual
Audi A6 2005 ➤
Audi A6 Avant 2005 ➤
Brake system
Edition 04.2019
Service
Service Department. Technical Information

List of Workshop Manual Repair Groups
Repair Group
00 - Technical data
45 - Anti-lock brake system
46 - Brakes - mechanism
47 - Brakes - hydraulics
Technical information should always be available to the foremen and mechanics, because their
careful and constant adherence to the instructions is essential to ensure vehicle road-worthiness and
safety. In addition, the normal basic safety precautions for working on motor vehicles must, as a
matter of course, be observed.
Service
All rights reserved.
No reproduction without prior agreement from publisher.
Copyright © 2019 Audi AG, Ingolstadt A005A600220

Contents
00 - Technical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1 Technical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
1.1 Allocation of PR number (factory code) to brake components . . . . . . . . . . . . . . . . . . . . . . 1
1.2 Brakes, technical data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2 Assessment of ceramic brake discs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.1 Visible features of ceramic brake discs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6
2.2 Superficial cracks in cooling channel lands . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7
2.3 Cracks in area of bolted connection on ceramic brake discs . . . . . . . . . . . . . . . . . . . . . . . . 7
2.4 Edge fractures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.5 Chipping on ceramic brake discs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
2.6 Cracks extending into cooling channels . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
3 Assessing degree of wear on ceramic brake discs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10
3.1 Wear assessment by checking thickness of brake disc . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.2 Wear assessment by checking thickness of brake disc . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
3.3 Wear assessment according to wear indicators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
3.4 Wear assessment by weighing brake disc . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15
3.5 Wear assessment of ceramic brake disc with tester VAS 6813 . . . . . . . . . . . . . . . . . . . . 16
4 Brake test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.1 General notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.2 Vehicles with front-wheel drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.3 Vehicles with four-wheel drive . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
4.4 Electromechanical parking brake on brake test equipment . . . . . . . . . . . . . . . . . . . . . . . . 24
5 Brake fluid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
5.1 General notes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
45 - Anti-lock brake system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
1 General information on the anti-lock brake system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
1.1 Notes for repair work on the ABS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26
2 Connecting vehicle diagnostic, testing and information system VAS 5051B or VAS 5052 and
selecting functions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
3 Exploded view - ABS/ESP components . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
4 Anti-lock brake system (ABS) Bosch 8.0 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
4.1 Hydraulic unit and brake lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35
4.2 Removing and installing hydraulic control unit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36
4.3 Removing and installing hydraulic control unit - S6 and RS 6 . . . . . . . . . . . . . . . . . . . . . . 40
5 Removing and installing parts of ABS system on front and rear axles . . . . . . . . . . . . . . . . 46
5.1 Removing and installing parts of ABS system on front axle . . . . . . . . . . . . . . . . . . . . . . . . 46
5.2 Removing and installing front wheel speed sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
5.3 Removing and installing parts of ABS system on rear axle . . . . . . . . . . . . . . . . . . . . . . . . 47
5.4 Removing and installing rear wheel speed sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
6 Removing and installing parts of ESP system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
6.1 Removing and installing brake light switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50
6.2 Removing and installing brake light sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
6.3 Removing and installing ESP sensor unit G419 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52
6.4 Removing and installing steering angle sender G85 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53
6.5 Removing and installing parking brake contact switch F321 . . . . . . . . . . . . . . . . . . . . . . . . 54
6.6 Removing and installing brake pressure sender G518 and brake pressure sender G519
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
46 - Brakes - mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
1 Front brakes FN3 (PR 1LT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
1.1 Servicing front brakes (PR 1LT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56
Audi A6 2005 ➤ , Audi A6 Avant 2005 ➤
Brake system - Edition 04.2019
Contents i

1.2 Removing and installing brake pads (1LT) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 58
2 Front brakes FNR G60 (PR 1LG/1LD/1LH/1LV/1ZL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
2.1 Servicing front brakes (PR 1LG/1LD/1LH/1LV/1ZL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
2.2 Removing and installing brake pads (PR 1LG/1LD/1LH/1LV/1ZL) . . . . . . . . . . . . . . . . . . 64
3 Front brakes (PR 1LJ/1LL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
3.1 Servicing front brakes (PR 1LJ/1LL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
3.2 Removing and installing brake pads (PR 1LJ/1LL) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72
4 Front brakes (steel version) - RS 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
4.1 Servicing front brakes (steel version) - RS 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77
4.2 Detaching and attaching front brake caliper - RS 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 78
4.3 Renewing front brake caliper (RS 6) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
4.4 Removing and installing front brake pads - RS 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
4.5 Detaching and attaching front brake disc - RS 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
4.6 Renewing front brake disc - RS 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
5 Ceramic front brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
5.1 Servicing ceramic front brakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
5.2 Detaching and attaching front brake caliper (ceramic brakes) . . . . . . . . . . . . . . . . . . . . . . 90
5.3 Renewing front brake caliper (ceramic brakes) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 92
5.4 Removing and installing front brake pads (ceramic brakes) . . . . . . . . . . . . . . . . . . . . . . . . 95
5.5 Detaching and attaching front brake disc (ceramic brakes) . . . . . . . . . . . . . . . . . . . . . . . . 100
5.6 Renewing front brake disc (ceramic brakes) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
6 Rear brakes, electronic parking brake and handbrake (EPB) . . . . . . . . . . . . . . . . . . . . . . 104
6.1 Servicing rear brakes (including ceramic brakes) - all models . . . . . . . . . . . . . . . . . . . . . . 104
6.2 Removing and installing brake pads . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
7 Exploded view - brake pedal, left-hand drive vehicles with manual gearbox . . . . . . . . . . . . 113
7.1 Removing and installing brake pedal - left-hand drive vehicles . . . . . . . . . . . . . . . . . . . . . . 114
8 Exploded view - brake pedal, left-hand drive vehicles with automatic gearbox . . . . . . . . . . 115
9 Exploded view - brake pedal, right-hand drive vehicles . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
9.1 Removing and installing brake pedal - right-hand drive vehicles . . . . . . . . . . . . . . . . . . . . 117
9.2 Separating brake pedal from brake servo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 118
10 Removing and installing mounting bracket . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
10.1 Removing and installing mounting bracket . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
11 Overview of components - electronic parking brake and handbrake (EPB) . . . . . . . . . . . . 124
11.1 Removing and installing electric park and handbrake control unit J540 . . . . . . . . . . . . . . 125
11.2 Removing and installing actuator motor for electronic parking brake and handbrake . . . . 126
47 - Brakes - hydraulics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
1 Pressurised leak test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
1.1 Pressurised leak test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
1.2 High-pressure and low-pressure tests . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
2 Brake caliper FN3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
2.1 Servicing brake calipers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 130
2.2 Removing and installing piston for front brake caliper . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
3 Brake caliper FNR G60 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
3.1 Servicing brake calipers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
3.2 Removing and installing piston for front brake caliper . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
4 Brake calipers 2FNR 42 AL . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
4.1 Servicing brake calipers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
4.2 Removing and installing piston for front brake caliper . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
5 Servicing brake calipers (steel version) - RS 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142
5.1 Removing and installing piston for front brake caliper . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142
6 Servicing front brake calipers (ceramic brakes) - RS 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
6.1 Removing and installing pistons for front brake caliper (ceramic brakes) . . . . . . . . . . . . . . 147
Audi A6 2005 ➤ , Audi A6 Avant 2005 ➤
Brake system - Edition 04.2019
ii Contents

7 Rear brake calipers for electronic parking brake and handbrake (EPB) . . . . . . . . . . . . . . 149
7.1 Servicing brake calipers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
7.2 Removing and installing piston for rear brake caliper . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150
8 Bleeding brake system . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 154
8.1 Bleeding hydraulic system with brake filling and bleeding equipment . . . . . . . . . . . . . . . . 155
8.2 Bleeding hydraulic system without brake filling and bleeding equipment . . . . . . . . . . . . . . 157
8.3 Changing brake fluid . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
9 Exploded view - brake servo / brake master cylinder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 160
10 Removing and installing brake master cylinder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
10.1 Removing and installing brake master cylinder . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
11 Brake servo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165
11.1 Removing and installing brake servo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165
12 Vacuum pumps for brake servo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
12.1 Exploded view - vacuum pump for brake servo . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
12.2 Removing and installing vacuum pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
12.3 Removing and installing vacuum pump - vehicles with 2.0 ltr. petrol engine . . . . . . . . . . 170
12.4 Removing and installing vacuum pump - vehicles with 2.4 ltr. petrol engine . . . . . . . . . . . . 173
12.5 Removing and installing vacuum pump - vehicles with 2.8 ltr. petrol engine . . . . . . . . . . . . 174
12.6 Removing and installing vacuum pump - vehicles with 3.0 ltr. petrol engine . . . . . . . . . . . . 175
12.7 Removing and installing vacuum pump - vehicles with 3.2 ltr. petrol engine . . . . . . . . . . . . 176
12.8 Exploded view - vacuum pump, RS 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177
12.9 Removing and installing vacuum pump - RS 6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 178
12.10 Removing and installing vacuum pump - vehicles with diesel engine . . . . . . . . . . . . . . . . 179
12.11 Removing and installing vacuum pump - vehicles with 2.7 ltr. TDI and 3.0 ltr. TDI diesel engine
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 181
13 Checking electric vacuum pump for brakes V192 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 183
13.1 Exploded view - electric vacuum pump for brakes V192 . . . . . . . . . . . . . . . . . . . . . . . . . . 185
13.2 Removing and installing electric vacuum pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185
13.3 Removing and installing electric vacuum pump - S6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188
13.4 Brake servo pressure sensor G294 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189
13.5 Removing and installing pressure sensor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189
13.6 Checking non-return valve . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190
13.7 Checking non-return valve - S6 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 190
14 Brake hoses and brake lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191
14.1 Routing of brake hoses/lines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 191
Audi A6 2005 ➤ , Audi A6 Avant 2005 ➤
Brake system - Edition 04.2019
Contents iii

Audi A6 2005 ➤ , Audi A6 Avant 2005 ➤
Brake system - Edition 04.2019
iv Contents

00 – Technical data
1 Technical data
(ARL006362; Edition 04.2019)
1.1 Allocation of PR number (factory code)
to brake components
The type of brake system installed in the vehicle is indicated by
the corresponding PR number on the vehicle data sticker.
The vehicle data sticker can be found in the spare wheel well and
in the Service Schedule.
Item -A- indicates the PR number of the front brakes.
Item -B- indicates the PR number of the rear brakes.
♦ For correct version refer to ⇒ ETKA
♦ The tables appearing below explain the PR numbers. These
are important to obtain the correct combination of brake cali‐
pers/brake discs and brake pads.
1.2 Brakes, technical data
Front brakes
Factory code (PR No.) 1LT 1LD 1LG/1LV 1LH/1ZL/
1ZT 1LJ/1LL 1)
Brake caliper FN-3 (16") FNR G60 16" FNR G60 16" FNR G60
17" 2 FNR 42 AL 18"
Brake disc, ventilated ∅
mm 314 321 321 347 385
Brake disc, thickness mm 25 30 30 30 36
Brake disc, wear limit mm 23 28 28 28 34
Brake caliper, piston ∅
mm 57 60 60 60 60
Brake pad thickness mm 19.5 20.24 20.24 20.24 20.43
Brake pad wear limit mm 3 4 4 4 4
Audi A6 2005 ➤ , Audi A6 Avant 2005 ➤
Brake system - Edition 04.2019
1. Technical data 1

Note
♦ Maximum lateral run-out of steel brake disc: 0.06 mm
♦ Perform measurement with brake disc installed.
♦ Use dial gauge bracket VAS 6079/1 and dial gauge VAS 6079.
♦ Remove any dirt and rust from brake disc.
♦ Perform measurement 10 mm from outer edge of brake disc.
⇒ “1 Front brakes FN3 (PR 1LT)”, page 56
⇒ “2 Front brakes FNR G60 (PR 1LG/1LD/1LH/1LV/1ZL)”,
page 62
⇒ “2 Front brakes FNR G60 (PR 1LG/1LD/1LH/1LV/1ZL)”,
page 62
⇒ “2 Front brakes FNR G60 (PR 1LG/1LD/1LH/1LV/1ZL)”,
page 62
⇒ “3 Front brakes (PR 1LJ/1LL)”, page 70
1) PR 1LL: special security vehicle
Front brakes (RS 6, steel version)
Factory code (PR
No.)
1LM
Brake caliper Brembo (19")
Brake disc, ventila‐
ted ∅ mm 390
Brake disc, thick‐
ness mm 36
Brake disc, wear
limit (mm) mm 34.4
Brake caliper, 6 pis‐
tons (mm) mm 6 pistons (2x ∅34; 2x ∅36; 2x ∅36 mm)
Brake pad thick‐
ness including
backplate (mm)
mm 16.62
Pad wear limit (in‐
cluding backplate) mm 9.5
Note
♦ Maximum lateral run-out of steel brake disc: 0.06 mm
♦ Perform measurement with brake disc installed.
♦ Use dial gauge bracket VAS 6079/1 and dial gauge VAS 6079.
♦ Remove any dirt and rust from brake disc.
♦ Perform measurement 10 mm from outer edge of brake disc.
Audi A6 2005 ➤ , Audi A6 Avant 2005 ➤
Brake system - Edition 04.2019
2 Rep. gr.00 - Technical data

⇒ “4 Front brakes (steel version) - RS 6”, page 77
Brake discs
Note
♦ When performing repair work on brakes, hairline cracks are
often found on the friction surface of the brake discs. Hairline
cracks up to a length of 10 mm do not present a technical
problem and do not justify a renewal of brake discs.
♦ Brake discs with cracks going all the way across the friction
surface must be renewed.
Ceramic front brakes
Factory code (PR
No.)
1LN
Brake disc, ventila‐
ted ∅ mm ∅ 420
Brake disc, thick‐
ness mm 40
Brake disc, wear
limit
The minimum thickness of the brake
disc is stamped onto the brake disc
hub as a wear limit specification.
Brake caliper, 8 pis‐
ton ∅ mm 8x ∅ 30.2
Brake pad thick‐
ness (including
backplate)
mm 20
Pad wear limit (in‐
cluding backplate) mm 10
Note
Hairline cracks on the friction surfaces of ceramic brakes can be
caused during manufacturing and therefore already appear to
varying degrees when the brakes are new. Hairline cracks on the
friction surfaces do not justify a renewal of the ceramic brake
discs.
⇒ “5 Ceramic front brakes”, page 88
Rear brakes
Factory code (PR No.) 1KD/1KQ/2ED 1KW/2EE/2EL
Brake caliper C41 (16”) C43 (17”)
Brake disc, ventilated ∅ mm 302 330
Brake disc, thickness mm 12 22
Brake disc, wear limit mm 10 20
Brake caliper, piston ∅ mm 41 41
Brake pad thickness mm 16.90 17.46
Brake pad wear limit mm 3 3
Audi A6 2005 ➤ , Audi A6 Avant 2005 ➤
Brake system - Edition 04.2019
1. Technical data 3

Note
♦ Maximum lateral run-out of steel brake disc: 0.06 mm
♦ Perform measurement with brake disc installed.
♦ Use dial gauge bracket VAS 6079/1 and dial gauge VAS 6079.
♦ Remove any dirt and rust from brake disc.
♦ Perform measurement 10 mm from outer edge of brake disc.
⇒ “6 Rear brakes, electronic parking brake and handbrake
(EPB)”, page 104
Rear brakes (RS 6, steel version)
Factory code (PR
No.)
1KJ
Brake caliper TRW C45 (19")
Brake disc, ventila‐
ted ∅ mm 356
Brake disc, thick‐
ness mm 28
Brake disc, wear
limit mm 26.4
Brake caliper, pis‐
ton ∅ mm 45
Brake pad thick‐
ness (including
backplate)
mm 16.9
Pad wear limit (in‐
cluding backplate) mm 9
Note
♦ Maximum lateral run-out of steel brake disc: 0.06 mm
♦ Perform measurement with brake disc installed.
♦ Use dial gauge bracket VAS 6079/1 and dial gauge VAS 6079.
♦ Remove any dirt and rust from brake disc.
♦ Perform measurement 10 mm from outer edge of brake disc.
⇒ “6 Rear brakes, electronic parking brake and handbrake
(EPB)”, page 104
Ceramic rear brakes
Brake caliper TRW C45 (20")
Factory code (PR
No.)
1KK
Brake disc, ventila‐
ted ∅ mm 356
Brake disc, thick‐
ness mm 28
Brake disc, wear
limit
The minimum thickness of the brake
disc is stamped onto the brake disc
hub as a wear limit specification.
Audi A6 2005 ➤ , Audi A6 Avant 2005 ➤
Brake system - Edition 04.2019
4 Rep. gr.00 - Technical data

Ceramic rear brakes
Brake caliper, 1 pis‐
ton ∅ mm ∅ 45
Brake pad thick‐
ness (including
backplate)
mm 16.9
Pad wear limit (in‐
cluding backplate) mm 9
Hairline cracks on the friction surfaces of ceramic brakes can be
caused during manufacturing and therefore already appear to
varying degrees when the brakes are new. Hairline cracks on the
friction surfaces do not justify a renewal of the ceramic brake
discs.
⇒ “6 Rear brakes, electronic parking brake and handbrake
(EPB)”, page 104
Audi A6 2005 ➤ , Audi A6 Avant 2005 ➤
Brake system - Edition 04.2019
1. Technical data 5

2 Assessment of ceramic brake discs
1 - Cooling channel lands
2 - Friction layer
3 - Carrier material
2.1 Visible features of ceramic brake discs
Checking area of bolted connection on friction ring and brake disc
hub:
WARNING
The brake disc rotor and the brake disc hub are bolted together
and must NOT be separated. DO NOT slacken the bolted con‐
nection on the brake disc hub.
Audi A6 2005 ➤ , Audi A6 Avant 2005 ➤
Brake system - Edition 04.2019
6 Rep. gr.00 - Technical data

Due to the production process there already are relaxation cracks
(varying degrees) on the friction surface of the brake disc when it
is new.
Note
Relaxation cracks on a ceramic brake disc do not constitute a
technical problem.
Even on new brake discs relaxation cracks may be clearly visible,
and their size can vary.
2.2 Superficial cracks in cooling channel
lands
Superficial cracks in the cooling channel lands -arrow- are caused
during manufacturing.
Note
Superficial cracks in the cooling channel lands do not constitute
a technical problem on the ceramic brake discs.
2.3 Cracks in area of bolted connection on
ceramic brake discs
Checking area of bolted connection on friction ring and brake disc
hub:
WARNING
The brake disc rotor and the brake disc hub are bolted together
and must NOT be separated. DO NOT slacken the bolted con‐
nection on the brake disc hub.
Audi A6 2005 ➤ , Audi A6 Avant 2005 ➤
Brake system - Edition 04.2019
2. Assessment of ceramic brake discs 7

Ceramic brake discs must be renewed if there are cracks in the
area of the bolted connection of the brake disc hub extending into
the friction surface of the brake disc -arrows-.
Ceramic brake discs must be renewed if there are radial cracks
in the area of the bolted connection on the brake disc hub.
WARNING
If one brake disc is damaged or worn, the other discs must also
be checked for damage and wear.
2.4 Edge fractures
Edge fractures -arrow- are caused by mechanical damage to the
edges.
Permissible:
♦ max. width/depth = 2 mm
♦ max. length = 20 mm
♦ max. 3 edge fractures per brake disc
If any of the criteria listed above are exceeded, the brake disc
must be renewed. ⇒ page 101
WARNING
If one brake disc is damaged or worn, the other discs must also
be checked for damage and wear.
2.5 Chipping on ceramic brake discs
Always renew ceramic brake discs if there is chipping (larger than
1 cm² -arrow-) on the friction surface.
WARNING
If one brake disc is damaged or worn, the other discs must also
be checked for damage and wear.
Audi A6 2005 ➤ , Audi A6 Avant 2005 ➤
Brake system - Edition 04.2019
8 Rep. gr.00 - Technical data

2.6 Cracks extending into cooling channels
Always renew ceramic brake discs if there is any cracking ex‐
tending from the friction surface of the brake disc to the cooling
channel or through the cooling channel.
Audi A6 2005 ➤ , Audi A6 Avant 2005 ➤
Brake system - Edition 04.2019
2. Assessment of ceramic brake discs 9

3 Assessing degree of wear on ceramic
brake discs
When minimum weight is stamped on hub of brake disc:
WARNING
The brake disc rotor and the brake disc hub are bolted together
and must NOT be separated. DO NOT slacken the bolted con‐
nection on the brake disc hub.
Designation of ceramic brake disc on brake disc hub
1 - Direction of rotation
2 - Supplier
3 - Serial production number of
brake disc
4 - Audi part number
Note
The Audi part number on this brake
disc is an example and can vary de‐
pending on the vehicle type and
model.
5 - Production date of brake
disc
6 - Permissible minimum thick‐
ness of brake disc
Note
The minimum permissible thickness
of the brake disc differs depending
on the type of vehicle.
7 - Weight of new brake disc
with brake disc hub
Checking area of bolted con‐
nection on friction ring and
brake disc hub:
WARNING
The brake disc rotor and
the brake disc hub are
bolted together and must
NOT be separated. DO
NOT slacken the bolted
connection on the brake
disc hub.
Audi A6 2005 ➤ , Audi A6 Avant 2005 ➤
Brake system - Edition 04.2019
10 Rep. gr.00 - Technical data

Note
Depending on the version, the min‐
imum permissible weight for a used
brake disc is stamped on the brake
disc hub. The disc must be renewed
when the weight of the disc is less
than or equal to the indicated mini‐
mum weight.
Caution
If the minimum permissi‐
ble weight of the disc is
indicated on the hub of
the disc (“min. weight”),
the disc must be addi‐
tionally weighed to as‐
sess the amount of wear.
WARNING
If one brake disc is dam‐
aged or worn, the other
discs must also be
checked for damage and
wear.
The brake disc must first be cleaned before assessing the degree
of wear as described below.
WARNING
DO NOT clean the brake disc with water or other fluids. Oth‐
erwise false results will be obtained.
Note
♦ The brake disc ventilation drillings must be completely free of
brake dust and dirt. Clear out carefully with a suitable tool if
necessary. Do not use force.
♦ Thoroughly blow out the brake discs with compressed air (in‐
cluding the area between the cooling channels and ventilation
drillings).
♦ Carefully place the clean, dry brake disc on the scales.
Caution
Always observe respiratory protection requirements when
cleaning brake discs or other parts of the brake system using
compressed air.
To assess the brake disc wear, proceed as follows:
♦ 1. Wear assessment by checking thickness of brake disc
Audi A6 2005 ➤ , Audi A6 Avant 2005 ➤
Brake system - Edition 04.2019
3. Assessing degree of wear on ceramic brake discs 11

♦ 2. Wear assessment according to wear indicators
1. Wear assessment by checking thickness of brake disc
⇒ page 13
Thickness of brake discs in permissible range → brake disc OK
Brake disc thickness in critical
range min. Th + 0.2 mm Value at or below limit
↓↓ ↓↓
Further wear assessment ac‐
cording to wear indicators Renew brake disc.
↓↓ ----------
2. Wear assessment according to wear indicators
⇒ page 14
None of the six wear indicators fully worn out → brake disc OK
---------- One of the six wear indicators
fully worn out
--------- ↓↓
---------- Renew brake disc.
Note
Depending on the version, the minimum permissible weight for a
used brake disc is stamped on the brake disc hub. The disc must
be renewed when the weight of the disc is less than or equal to
the indicated minimum weight.
Caution
If the minimum permissible weight of the disc is indicated on
the hub of the disc (“min. weight”), the disc must be additionally
weighed to assess the amount of wear. The disc must be re‐
newed when the weight of the disc is less than or equal to the
indicated minimum weight.
Brake disc with minimum weight stamped on hub:
To assess the wear of the brake disc, proceed as follows:
♦ 1. Wear assessment by checking thickness of brake disc
♦ 2. Wear assessment according to wear indicators
♦ 3. Wear assessment by weighing brake disc
1. Wear assessment by checking thickness of brake disc (if
minimum weight is stamped on hub) ⇒ page 13
Thickness of brake discs in permissible range → brake disc OK
Brake disc thickness in critical
range min. Th + 0.05 mm Value at or below limit
↓↓ ↓↓
Further wear assessment ac‐
cording to wear indicators Renew brake disc
↓↓ ----------
2. Wear assessment according to wear indicators
⇒ page 14
None of the six wear indicators fully worn out → brake disc OK
---------- One of the six wear indicators
fully worn out
Audi A6 2005 ➤ , Audi A6 Avant 2005 ➤
Brake system - Edition 04.2019
12 Rep. gr.00 - Technical data

--------- ↓↓
---------- 3. Weighing brake disc
⇒ page 15
---------- Minimum weight not reached
---------- ↓↓
---------- Brake disc OK
---------- Minimum weight reached
---------- ↓↓
---------- Renew brake disc
If one of the three wear limits defined below has been reached,
do NOT continue using the brake disc.
The brake disc must be renewed.
WARNING
If one brake disc is damaged or worn, the other discs must also
be checked for damage and wear.
3.1 Wear assessment by checking thick‐
ness of brake disc
Special tools and workshop equipment required
♦ Use a commercially available caliper gauge or micrometer
gauge.
The minimum permissible thickness of the brake disc is engraved
as “min.th.” on the brake disc hub.
– Measure the brake disc thickness -x- at three points on the
periphery next to the individual wear indicators.--
Note
If the thickness is x = min. th. + 0.2 mm, additionally check the
wear of the brake disc by inspecting the wear indicators
⇒ page 14 .
If the thickness of the brake disc is less than or equal to the min‐
imum permissible thickness “min.th.”, do NOT continue using the
brake disc. The brake disc must be renewed.
WARNING
If one brake disc is damaged or worn, the other discs must also
be checked for damage and wear.
3.2 Wear assessment by checking thick‐
ness of brake disc
Brake disc with minimum weight stamped on hub:
Special tools and workshop equipment required
♦ Use a commercially available caliper gauge or micrometer
gauge.
Audi A6 2005 ➤ , Audi A6 Avant 2005 ➤
Brake system - Edition 04.2019
3. Assessing degree of wear on ceramic brake discs 13

Measurement of the brake disc thickness involves removing the
brake discs.
The minimum permissible thickness of the brake disc is engraved
as “min.th.” on the brake disc hub.
– The brake disc thickness should be measured at three points
on the periphery next to the individual wear indicators -x-.
If the values are at or below these limits, the brake discs must be
renewed. It is no longer permissible to use these brake discs.
Brake disc with minimum weight stamped on hub:
Note
If the thickness x = “min. th.” + 0.05 mm, additionally check the
wear of the brake disc by inspecting the wear indicators
⇒ “3.3 Wear assessment according to wear indicators”,
page 14 .
WARNING
If one brake disc is damaged or worn, the other discs must also
be checked for damage and wear.
3.3 Wear assessment according to wear in‐
dicators
Wear indicators are positioned at intervals of 120 degrees on the
friction surfaces of the brake disc.
The wear indicators -arrow- appear in a different colour.
There are three indicators on each side of the brake disc (outside
and inside).
The following illustration shows a wear indicator on a disc that has
not reached the wear limit.
The wear on the ceramic brake disc appears as a dark, burnt out
recess at the wear indicator.
Do NOT continue using the brake disc if one of the six indicators
is completely burnt out. The brake disc must be renewed.
Audi A6 2005 ➤ , Audi A6 Avant 2005 ➤
Brake system - Edition 04.2019
14 Rep. gr.00 - Technical data