spongy brake pedal on allroad

**9eleven** · 13-05-2009,12:28 PM

Hi all

I am new to forums generally and certainly to this site but thought I would give it a go.

I have a 2004 Allroad tdi 2.5 auto 180 bhp that has just had pads replaced as they needed doing and pedal had begun to feel week.

Since having new pads I still think the pedal feels spongy/week even though I have bedded the new pads in.

The pedal gets better as you pump it but then sinks slightly when you hold it down? I know it is not leaking fluid as I have not had to top it up at all since I bought it several months ago. Somebody said it may be a faulty master cylinder or ABS but how will I know which, if any, without going to great expense of trial and error, part replacement?

Can anybody assist????

**Peter D** · 13-05-2009,01:58 PM

Two thought here, Did the garage open the bleed nipple when the pistons were pressed back. ?? I would suggest you have the whole system bled and then take it from there. Regards Peter

**9eleven** · 13-05-2009,04:13 PM

Hi Peter

thanks for your response. I have just spoken to the garage and he says he did open the nipple when pushing piston back as he would not have been able to move the pistons otherwise. I have therefore taken your advice and am now going to have him bleed the system next tuesday so fingers crossed that cures it!

Many thanks again.

Regards

Javid

**srrc** · 01-07-2009,09:48 PM

Did you fix the spongy brake pedal problem?
My 04 2.5tdi Allroad has had exactly the same thing happen. Change of pads and the car comes back with a pedal that will go all the way to the floor!
Garage say nothing wrong, but to keep me happy they took it round to the main dealer in Taunton who, to add insult to injury, said it was fine and all A6 brakes feel spongy!
Being taken for a moron by the main dealer is why I never go near them. But that's another topic.

Is it as simple as they let air in when opening the bleed screw?

**9eleven** · 01-07-2009,10:22 PM

hi srrc,

no i have not managed to sort them yet. I had them bled but that has not improved them.

My local garage whom I trust and know well says the same ie Audi brakes do tend to be spongy but I think there is something else the matter, yours do sound worse though!

The next things to try if cash permits is new master cylinder or ABS according to my mechanic, but he says to live with it for a while longer to allow the new pads to bed in and take slight ridges out of the discs as they will not help.

Another and possibly cheaper option is to try new disc's, so will keep plodding.

Let me know how you get on. Good luck.

**Peter D** · 02-07-2009,10:14 AM

Normally Audi brakes are sharp and not at all spongy. If the new pads had been fitted to corroded discs, particularly the inside surface which tend to corrode faster, then you will get a spongy response. I assume that if you brake hard your ABS is kicking in. Regards Peter

**srrc** · 02-07-2009,12:48 PM

Thanks all.
The initial pad change was indeed onto old discs, they stayed spongy after a bedding in period so I had them change the discs as well. Used all gen Audi bits.
The garage says they have bled the system, but air still seems the most likely reason.
Is it difficult to bleed these brakes?

**Peter D** · 02-07-2009,01:40 PM

AS they have bled the system then I would expect the brakes to be sharp. I have an A6 presently with new pads and discs and can assure you that they stop really well. Did you check the ABS and sis the brakes feel better afterwards. Also do a vacuum test as you have a TDI and the vacuum is generated not derived form the inlet manifold. Audi should have checked that leave the car one hour then recheck the brake servo still operates,i.e. the sevo holding the vacuum. The pump the brakes 10 times and hold the last pump then start the engine, the pedal should drop, tell be how far it drops. I assume that you can get a rock hard pedal with the engine off. Regards Peter

**srrc** · 02-07-2009,06:38 PM

Peter
Thanks for your help.
Done as you suggested.
Car had been standing overnight, 10 pumps brake pedal had normal travel to solid. Keeping my foot down started engine, pedal softened immediately and went to the floor.

Steve