A4 B5 2.5 Tdi Saloon - ABS system Bleeding ?

[kevmayer]

I've done a lot of work on the brake system of my 10 year old A4 saloon to prepare it for MOT.

I changed all disks and pads. Replaced all 6 flexible brake hoses and, because of corroded pipe ends, I had to change one rear brake pipe and both front brake pipes.

To do the front brake pipes I had to disconnect all 6 pipes from the ABS unit to remove it so I could get to the brake pipes which run down the back of this ABS block.

Now I've replaced the ABS block and refitted all the brake pipes. I've used a pressure bleeder to bleed the system in the order Rear Right, Rear Left, Front Right and, last of all , Front Left.

I have VAG COM and connected to the ABS (unit 03) and tried to do the ABS unit bleed by selecting

[Select]
[03 - ABS Brakes]
[Basic Settings - 04]
Group 002
[Go!]

But, I can't find any groups when I get to Basic Settings. I also read on a forum that the ABS Units of older A4s can't be bled using VAG COM.

The problem is that when I drive the car the brake pedal feels very spongy and it feels like the ABS is cutting in at low speed. So, I tried to remove all my ABS sensors to clean them. The rear ones came out ok and so did the front passenger side. I cleaned these three but, I broke the sensor on the driver's side, so I need to get a new one.

My question is, How can I bleed the ABS unit if VAG COM can't do it ?

I'd like to bleed the ABS and then repeat the bleed of the pipes.

cheers, Kevin

[towcestervag]

i dont use vagcom yet but on my 1552 its basic setting then001

[kevmayer]

Thanks for the reply.

I'm not sure what a 1552 is. Is it a fault code reader?

[towcestervag]

its the original VW hand held fault code reader which does all memories on the car and programmes

[kevmayer]

The front right ABS sensor was very difficult to get out. It broke up in the end and had to be extracted in pieces using a screwdriver as a chizzel and some long nose pliers.

Unfortunately I damaged the copper cage in the process, so, I need a new ABS Sensor Clamping Sleeve (i.e. copper cage).

Do AUDI dealers still sell these copper cages ?

[towcestervag]

dont know as never changed sleeve

[ginna_104]

hi ive got a abs sensor for sale genuine audi click on this link it's on ebay at the moment but in don't come with the copper insert.

http://cgi.ebay.co.uk/ws/eBayISAPI.d...m=150352202699

[kevmayer]

Thanks for the chance to buy your sensor ginna, but, I'm afraid I've already got one from GSF. I also managed to get the copper sleeves from Audi at £10.70 each.

I've cleaned all ABS sensors and changed the front right sensor. The brakes now feel ok. I think that cleaning the sensors has done the job.

Thanks for the replies.

Kevin

[kevmayer]

Latest update...

Although the ABS appeared to work ok, my brake pedal was still very spongy. So, I bled the brakes a second time, making sure that I drained off around 200ml from each corner. Although I didn't see any bubbles come out, the pedal is now good and firm and the whole braking system feels like new.

Bleeding for the second time appears to have done the trick.

Cheers, Kev