New Servo but brakes still wooden

[widdy]

After picking up my A4 Avant, the brakes where a bit rubbish and needed a lot of effort to brake, and there was very little feel to the braking.
The servos been replaced and the system bled but the brakes still have very little feel to them and at times its very difficult to brake.
i have pedal travel of about 1-2 inches and then i'm literally standing on the brakes willing the car to stop.
The rear n/s wheel is slightly warmer than the other 3 after stopping so not sure if i've got a binding issue or just crappy brakes.
cant remember my brakes being this bad in my 80 coupe or a3.

any ideas? most posts suggest the servo but thats been replaced.

many thanks in advance

it's a 2002 1.9 tdi

 

[pauldazzle]

Check the Vacuum pipes as it sounds like you have leak somewhere.

 

[widdy]

Check the Vacuum pipes as it sounds like you have leak somewhere.

will this show on a VCDS or Foxwell?

 

[pauldazzle]

No diagnostics won't help you, only physical inspection or a vacuum gauge will help..Smoke test is also be a good way to help pinpoint the leak.
There are a bunch of braided vacuum pipes that are notorious for splitting, & some are connected to the brake booster. Easiest thing is to just replace them all. I just bought a few meter's of 3mm & 4mm braided pipe & cut them to the required length. There are a couple of connecting T pieces that can break as well. Hard plastic pipe that connects to the Servo can split too.

 

[pauldazzle]

This is what I used.

http://www.ebay.co.uk/itm/221513013...49&var=520365864887&ssPageName=STRK:MEBIDX:IT
http://www.ebay.co.uk/itm/221513013...49&var=520365864887&ssPageName=STRK:MEBIDX:IT

 

[david7m]

Have you checked the discs and pads condition?
Could the pads be contaminated?
Dave

 

[widdy]

pads may well be contaminated, i'll check then shortly and in the meantime replace the vacuum hoses.

strangely enough was driving my SDI mk4 golf earlier thinking these brakes are way softer and have more brake lever play than my A4, 10 minutes later i'm on the side of the road as a brake hose had burst and i had no brakes, you couldnt make it up

 

[Broken Byzan]

i'd be checking the vacuum pump, I'd guess it's not working

 

[widdy]

right been to audi and ordered the brake vacuum hose from servo to bulkhead and from bulkhead to vacuum pump (£32 each) and braided hose on ebay order.

praying its not the vacuum pump........

 

[Ollie-B]

A very very common issue with this in my old garage. There is a one way valve near the bulkhead that breaks down (small black and white thing in the vacuum system) this makes the brake pedal hard

 

[Ollie-B]

Looks like this. Take it off and if you can blow through it both ways it's broken. Or someone might have put it on the wrong way at some point

 

[widdy]

Looks like this. Take it off and if you can blow through it both ways it's broken. Or someone might have put it on the wrong way at some point

cheers for that , gave it a quick blow this morning whilst changing the hoses over, it was still one way , some of the hoses where in a bad way

the brakes have a bit more feel to them but i've noticed the N239 valve solienoid doesn't have an end cap on it so its exposed to air...

getting there slowly

 

[BigCat]

Had this problem too. Turned out to be one of vac hoses had a leak...very hard to see..but i know i had vac pump gasket changed aswell...hope this helps...

 

[widdy]

Had this problem too. Turned out to be one of vac hoses had a leak...very hard to see..but i know i had vac pump gasket changed aswell...hope this helps...

So just the PD pump gasket not the actual pump? i've got a bit of oil seepage around there but thought i's have to change the pump. how did you know it was just the gasket was it presure tested?

 

[BigCat]

I had already changed out brake servo + hoses..figured for the price of a gasket 5 or 6 quid would try it before changing pump. No pressure test, i'm not a mechanic...lol..just got lucky mate...

 

[vfr750]

Mine was like that and it turned out to be the vac pump which was knackered and the servo.

 

[widdy]

UPdate
after a chat with the local Audi garage tech he said that if you pump the pedal three times and its like a brick on the third pump then the PD pump is gone.

Ordered Bosch PD pump from Germany £190 just waiting to fit it

Also bought myself a shiny new Foxwell and have spend many happy hour cycling through the menus