I just got my A8 out of the Mr. Transmission shop on Friday and it drives great. I have to say, I was a bit skeptical of using the shop to begin with, but they offer a 3 year, 36,000 mile warranty including annual check ups. The price was not cheap, but less than what Cottman and a few other shops were charging.

Anyway, I get the car back and remember that before it went in the shop to get the trans "fixed" I found the location of an oil leak I was having. It was coming from a breather hose in the rear of the engine(instead of paying $80 at the dealer I replaced it with the red hose you see in the pic). As far as I can tell the leak is no more.

Here's my problem... when I was trying to figure out how to get my hand down in the hole to replace the breather hose, I decided to loosen another hose so I could fit my hand down around the breather hose. The hose I loosened is the one with the red arrow pointing to it. I have no idea what hose this is, and I realize that was a stupid move on my part. As I was loosening it, some fluid started coming out so I quickly tightened it back down and didnt think much else about it... that is, until I went to drive the car and the brakes were hard as hell to push all the way down. It feels like there is major pressure in the lines or something. Since my brake fluid hasn't been bled out and replaced since I've owned the car and it was pretty dark, I decided to try my luck with bleeding the lines on all four wheels and get some new fluid in the reservoir. I went thru the motions (as instructed on the audipages site) and hoped this would maybe fix the problem. Unfortunately, it did not fix the problem.

Can anyone tell me what hose is the one with the arrow pointing towards it and does my loosening it have anything to do with my hard braking problem? I thought it could just be a coincidence and my loosening the hose and tightening it back down may have nothing whatsoever to do with the braking problem I'm now having. I just spent a lot of money on my car for the transmission and I don't want to have to spend any more money on it if I can help it. PLEASE HELP ME!

 

Those are the heater core hoses. The brake booster hose is the one on top of them. Just follow it to the intake and see if it is cracked or disconnected.

 

That is a coolant hose going to your heater cores...notice the bleeder valve on top, used to bleed air out when refilling coolant after draining system. Nothing to do with braking.

It sounds like you're describing brakes with no vacuum assist...like the feel of trying to stop the car with the engine off(?). Look to see (or hear while engine running)if a large black vacuum line is loose/torn/disconnected on or leading to the brake booster (large black "disk" unit) under/behind the brake fluid reservoir. Don't know what year your car is, but looks like this vacuum hose (.3 - .5 inch thick) runs over the top of your other hose with arrow and connects to the upper rear of the engine...look at all those connections.
Not sure if that's the vacuum hose in question (probably is)...mine runs under those coolant hoses and no vacuum line over the hoses...it's an '01 A8.

 

Woop, didn't mean to interrupt there tozoM8. I was typin my wordy response while you were posting...didn't see ya there.

 

No worries. Yes, the booster hose supposed to be under the coolant lines.

 

Thanks for the help/suggestions. I will give it a look and see if any of the hoses around the brake booster are loose or torn. To answer your question, its a 99 A8 4.2 and it has about 145k miles.