Soft brakes after all 4 calipers rebuilt - 2001 Mk1 Audi TT Quattro

[RussAdams]

Hi all!

I'm looking for some advice on how to completely bleed the brakes on my 2001 Audi TT Mk1 Quattro.

I just completely rebuilt all 4 calipers. In the process I didn't pinch off the brake lines and allowed the master cylinder to empty. Following the Bentley manual procedure, I simultaneously bled both front brakes, then simultaneously bled both rear brakes. Then Left Front, Right Front, Left Rear, Right Rear. Per the Bentley manual.

The brakes are very soft.

Do I need to do something with VCDS and the ABS system to get the brakes to bleed properly? Anyone have a link to the correct procedure?

Here's an autoscan I just took: (What is that 65535 - Internal Control Module Memory Error 00-00 - - AWD code?)

Friday,28,January,2022,15:06:51:26743
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 10 x64
VCDS Version: 21.9.0.2 (x64) HEX-V2 CB: 0.4555.4
Data version: 20210903 DS330.0
www.Ross-Tech.com


Mileage: 124260km-77211mi Repair Order:


Chassis Type: 8N - Audi TT (1999 > 2007)
Scan: 01 02 03 08 15 17 22 35 37 45 55 56 76 77

Mileage: 124260km-77211miles
-------------------------------------------------------------------------------
Address 01: Engine Labels: 06A-906-032-AMU.lbl
Part No: 8N0 906 018 T
Component: 1.8L R4/5VT G01 0003
Coding: 06710
Shop #: WSC 06158
VCID: 42DE4251CD99566BF15-513C

No fault code found.
Readiness: 0110 1101

-------------------------------------------------------------------------------
Address 03: ABS Brakes Labels: 8N0-907-379-MK20-E.clb
Part No: 8N0 907 379 E
Component: ESP 20 CAN V004
Coding: 18446
Shop #: WSC 01236
VCID: 3E2636A1B961328B95D-4AE0

No fault code found.

-------------------------------------------------------------------------------
Address 08: Auto HVAC Labels: 8N0-820-043.lbl
Part No: 8N0 820 043 A
Component: TT-KLIMAVOLLAUTOMAT D03
Coding: 00140
Shop #: WSC 01236
VCID: 280AF0F94BE59C3BCF1-2580

No fault code found.

-------------------------------------------------------------------------------
Address 15: Airbags Labels: 8N8-909-601.lbl
Part No: 8N8 909 601
Component: Airbag Front+Seite 1005
Coding: 10102
Shop #: WSC 01236
VCID: 77A8E385D6DBC3C396B-5118

No fault code found.

-------------------------------------------------------------------------------
Address 17: Instruments Labels: 8Nx-920-xxx-17.lbl
Part No: 8N1 920 930 E
Component: KOMBI+WEGFAHRS. M73 D10
Coding: 07244
Shop #: WSC 06417
VCID: 333017958223EFE36A3-4B00

No fault code found.

-------------------------------------------------------------------------------
Address 22: AWD Labels: 02D-900-554.lbl
Part No: 02D 900 554 D
Component: HALDEX LSC ECC 0011
VCID: 211CEDDD28DF6D7388F-4B00

1 Fault Found:
65535 - Internal Control Module Memory Error
00-00 - -

-------------------------------------------------------------------------------
Address 35: Centr. Locks Labels:. 8Nx-962-267.lbl
Part No: 8N7 962 267 A
Component: Central Lock/Alarm D04
Coding: 15900
Shop #: WSC 01236
VCID: 3E2636A1B961328B95D-4EEA

No fault code found.

-------------------------------------------------------------------------------
Address 45: Inter. Monitor Labels: 8E0-951-177.lbl
Part No: 8N7 951 177
Component: Innenraumueberw. D14
Coding: 00001
Shop #: WSC 00000
VCID: 7BA0FFB5EAF3E7A3F23-51CE

No fault code found.

-------------------------------------------------------------------------------
Address 56: Radio Labels: 8D0-035-1xx-56.lbl
Part No: 4B0 035 186 A
Component: Radio D02
Coding: 00117
Shop #: WSC 06335
VCID: 1E66D62119A1528BB5D-4B1E

No fault code found.

End----(Elapsed Time: 02:28, VBatt start/end: 11.9V/11.9V. VIgn 12.0V)-----


I'm working to get my TT in tiptop condition and sell it. Want to put that money into my "new to me" S4.

Thanks so much for any help! Russ

[usmcfieldmp]

I have a bit of the same problem (mushy pedal), but I think mine is due to the stock rubber brake lines needing to be replaced.

I haven't done an ABS cycle on this car, but did one on my B8.5 S5. It should be fairly easy and likely very similar. I'll see if I can find the old DIY that I used on this forum.

Do you have access to a vacuum bleeder? You can pick up a MityVac from somewhere like Harbor Freight for about $50. You'll also need an adapter to fit onto the brake reservoir. Vacuum bleeding can be useful in a situation like this, as well.

Sometimes just taking it out and driving it rough can free up some of the air bubbles, and then you just need to go out afterwards and rebleed. Not a dependable solution, but sometimes it works.

[RussAdams]

I was having trouble interpreting the correct bleeding sequence from the manual.

When the manual says to pump the pedal, I couldn’t decipher if this with the bleeder valves OPEN or CLOSED.

So I finally quit reading and just went forward. VCDS software actually walked me through the procedure! Yea!

I used a Motive power bleeder (looks somewhat like a garden sprayer with a pressure gauge), and Ross-Tech VCDS.

Here’s what I did:
1. All bleeder valves were CLOSED
2. Attach power bleeder and keep under 1 BAR (I’m using 10 psi)
3. Connect VCDS, turn ignition on and from the Main Screen select the [Auto-Scan] button, I chose Chassis 8N - Audi TT (1999 > 2007) within auto scan
4. Return to Main Screen and select the [Select] button
5. Within Select Control Module select the [03-ABS Brakes] button
6. Within the 03-ABS Brakes select [Basic Settings – 04]
7. VCDS now shows Group 000 and nothing. I clicked the [Up] button and got
Group 001 Brake Pump Bleeding
Instructions! Yea!
Press Pedal and Hold…
When I pressed the pedal it went to the floor, then the pump kicked in and pushed against my foot. When it settled down and stopped doing its thing, it read:
Release Pedal FR+FL bleed Screws OPEN
8. So I put pans under the bleeder valves and opened both FRONT bleeder screws and let flow til clear of bubbles and spitting. A nice clear stream of brake fluid. Power bleeder is still connected at 10 psi.
9. Then CLOSE both FRONT bleeder screws and return to VCDS and clicked [Up]
Which switched to group 002 Starting Wheel Speed (???) and got more instructions:
Press Pedal 10 Times Bleed Screws CLOSE
I pressed the pedal 10 times then clicked [Up} and got more instructions on Group 03:Press Pedal and Hold…
10. Which then switched to Release Pedal FR+FL bleed Screws OPEN
11. Ok… so I did that and a little more air did escape from the system. Then I switched to the regular bleeding instructions:
12. Using a power bleeder, for each caliper in this sequence: LF, RF, LR, RR:
- open bleeder screw and let it flow until no more bubbles
- with bleeder screw open, slowly pump brake pedal 5 times
- close bleeder screw and replace rubber cap and move on to next caliper
Most complicated brake bleed I’ve ever done!!!
Then I took it for a road test and re-performed the seating procedure for new pads and rotors. 4 cycles of running up to 45 mph, then moderate braking to 15 mph. Followed by 10 cycles of running up to 60 mph, then HARD breaking to 15 mph… coast a bit and repeat until 10 cycles are completed. Then drive for 5 to 10 minutes to let the brakes cool.

Here's the scan after:
Monday,31,January,2022,13:59:55:26743
VCDS -- Windows Based VAG/VAS Emulator Running on Windows 10 x64
VCDS Version: 21.9.0.2 (x64) HEX-V2 CB: 0.4555.4
Data version: 20210903 DS330.0
www.Ross-Tech.com


Mileage: 124290km-77230mi Repair Order:



--------------------------------------------------------------------------------
--------------------------------------------------------------------------------


Chassis Type: 8N - Audi TT (1999 > 2007)
Scan: 01 02 03 08 15 17 22 35 37 45 55 56 76 77

Mileage: 124290km-77230miles
-------------------------------------------------------------------------------
Address 01: Engine Labels: 06A-906-032-AMU.lbl
Part No: 8N0 906 018 T
Component: 1.8L R4/5VT G01 0003
Coding: 06710
Shop #: WSC 06158
VCID: 42DE4251CD99566BF15-513C

No fault code found.
Readiness: 0000 1000

-------------------------------------------------------------------------------
Address 03: ABS Brakes Labels: 8N0-907-379-MK20-E.clb
Part No: 8N0 907 379 E
Component: ESP 20 CAN V004
Coding: 18446
Shop #: WSC 01236
VCID: 3E2636A1B961328B95D-4AE0

No fault code found.

-------------------------------------------------------------------------------
Address 08: Auto HVAC Labels: 8N0-820-043.lbl
Part No: 8N0 820 043 A
Component: TT-KLIMAVOLLAUTOMAT D03
Coding: 00140
Shop #: WSC 01236
VCID: 280AF0F94BE59C3BCF1-2580

No fault code found.

-------------------------------------------------------------------------------
Address 15: Airbags Labels: 8N8-909-601.lbl
Part No: 8N8 909 601
Component: Airbag Front+Seite 1005
Coding: 10102
Shop #: WSC 01236
VCID: 77A8E385D6DBC3C396B-513C

No fault code found.

-------------------------------------------------------------------------------
Address 17: Instruments Labels: 8Nx-920-xxx-17.lbl
Part No: 8N1 920 930 E
Component: KOMBI+WEGFAHRS. M73 D10
Coding: 07244
Shop #: WSC 06417
VCID: 333017958223EFE36A3-4B00

No fault code found.

-------------------------------------------------------------------------------
Address 22: AWD Labels: 02D-900-554.lbl
Part No: 02D 900 554 D
Component: HALDEX LSC ECC 0011
VCID: 211CEDDD28DF6D7388F-4B00

2 Faults Found:
65535 - Internal Control Module Memory Error
00-00 - -
00532 - Supply Voltage B+
07-10 - Signal too Low - Intermittent

-------------------------------------------------------------------------------
Address 35: Centr. Locks Labels:. 8Nx-962-267.lbl
Part No: 8N7 962 267 A
Component: Central Lock/Alarm D04
Coding: 15900
Shop #: WSC 01236
VCID: 3E2636A1B961328B95D-4EEA

No fault code found.

-------------------------------------------------------------------------------
Address 45: Inter. Monitor Labels: 8E0-951-177.lbl
Part No: 8N7 951 177
Component: Innenraumueberw. D14
Coding: 00001
Shop #: WSC 00000
VCID: 7BA0FFB5EAF3E7A3F23-51CE

No fault code found.

-------------------------------------------------------------------------------
Address 56: Radio Labels: 8D0-035-1xx-56.lbl
Part No: 4B0 035 186 A
Component: Radio D02
Coding: 00117
Shop #: WSC 06335
VCID: 1E66D62119A1528BB5D-4B1E

No fault code found.

End----------(Elapsed Time: 02:29, VBatt start/end: 12.5V/12.5V)-----------


I'll chase the Haldex issues in a different thread.

[RussAdams]

I have a bit of the same problem (mushy pedal), but I think mine is due to the stock rubber brake lines needing to be replaced.

I haven't done an ABS cycle on this car, but did one on my B8.5 S5. It should be fairly easy and likely very similar. I'll see if I can find the old DIY that I used on this forum.

Do you have access to a vacuum bleeder? You can pick up a MityVac from somewhere like Harbor Freight for about $50. You'll also need an adapter to fit onto the brake reservoir. Vacuum bleeding can be useful in a situation like this, as well.

Sometimes just taking it out and driving it rough can free up some of the air bubbles, and then you just need to go out afterwards and rebleed. Not a dependable solution, but sometimes it works.

Thanks for the advice! I did run it hard, but didn't have any luck until following through the procedures for when the master cylinder has gone empty. Never could find a clear step by step. Think the manual writers expect more knowledge than what I have. I'm a decent back yard mechanic, but when it doesn't work I need clearer instructions. VCDS was really helpful by telling me when to open/close and pump the brakes.

I'm happy with the brakes now. Need to sort out what is going on with the Haldex tho. Really enjoyed reading through your build thread! TT's are really fun cars. I just need a convertible I can take the girlfriend AND German Shepard in at the same time. LOL.

[usmcfieldmp]

Think the manual writers expect more knowledge than what I have. I'm a decent back yard mechanic, but when it doesn't work I need clearer instructions.

Same.

And thanks. Glad you enjoyed the thread. Definitely fun cars.