A4 1999 Avant 1.8t quattro. The brake pads were getting thin so I replaced all the pads and the front rotors. Fronts were a snap, the rears needed the compression tool which I rented from the local auto parts store. All that seemed to go fine.

I bled the brakes starting with the furthest caliper (right-rear) and worked my way to the fronts. I was able to get plenty of fluid transferring and purged all the old fluid out. No bubbles were seen as I kept the reservoir full. I did the old school method with a partner at the driver's seat and me at the caliper turing a 7/16 boxed-end wrench calling "Up", "Down".

Now my brakes are spongy, not as SOLID as they were before. I did a second bleeding but still have the same results.

In some of the BMWs, it's difficult to get a good bleed because of the ABS system. I'm wondering if Audi has a similar problem. Should I be bleeding with the engine running to create a vacuum at the master diaphragm? Obviously I'm missing something, probably very simple - I just don't know what.

Any advice?

 

There is a way of bleeding the ABS module but I believe it requires Vagcom to do it.

 

you must noit have bled them well enough its almost impossible to get air into the abs. I have bled audi brakes about ten times in the last month and haven't bled the abs once. It helps to bleed the clutch first since thats on the same reservoir, but i just bled mine yesterday old fashion push and hold and they work great no sponge. This is a after a full fluid drain aswell.

 

First off if new pads were installed without new brake rotors the pad to rotor contact will be off until the pads have a chance to bed themselves with the rotors.
Second , i would check & make sure the pads move freely in the caliper brackets & that the calipers pins are not sticky or frozen. Either one of those items can give you a spongy brake pedal assuming all the air has been removed.

 

and you greased the slide pins correct?

 

he replace pads and rotors...second sentence

 

I had the same problem until I bled mine the opposite direction. On these cars I've read that you should start with the wheel nearest the master cylinder and then move to the one furthest. FL-FR-RL-RR.

I bled mine using a homemade pressure bleeder that made it really easy. I have heard that using the two person pedal technique can damage the seals in the master cylinder because the piston is compressed further than typical.

 

I've heard the opposite. furthest away on audis its usually nearest but either way the air is escaping. Try what bshuted say and do it starting with nearest the cylinder.

 

I forgot to mention - this is an automatic trans. No clutch.
What is the "Push and Hold" method?
Could my spongyness be something other than ABS?

 

I can see a tiny bit of deflection with imperfect new surfaces until wear-in. I have driven the car around the neigorhood to assist the break-in. This spongyness feels like air in the lines. I can pump up the brakes and they get solid. Unfortunately, it gets soft after 10 seconds.

Regarding the pins, yes I cleaned then and coated them with light oil before installation. I don't think excessive friction or misalignment is the problem there.