2G 95 TSI AWD Brake System Problems

[hellotbone]

OK so I started out today with changing the calipers. My stock ones snapped the bleeders off so I had a set of rear brakes complete from my parts car. My car has the early crappy rotors so the parts car had the better slotted ones so that meant calipers and brackets too. Everything on well and painted time to bleed time for problems.

Ok here is what happens bleed and bleed and bleed and get all the air out or so we think as of now no air comes at all. Car off peddle is hard in first push and you can hold it and there is NO fade at all just holds near the top all nice and happy.

Start the car the peddle immiedatly fades to 3/4 of the way down and holds let go and let it sit for 30 seconds hit it and peddle fades to the floor.

Tested booster as per manual and it checks out fine. Tested check valve in vac line fine.

Rebuilt master cylinder (after the problem) thought it was that still there.

Any sugguestions????

 

[AWDPetmitsu]

Did you bleed ALL of the calipers? Did you follow the proper bleeding procedure? Did you have someone help you bleed them? I'm pretty sure you didn't bleed the brake system correctly and there is still air in the lines.

 

[ADrewzki]

For what it's worth, I always bleed mine with the key in the "on" position. I've heard people gravity bleeding as well with good results.

 

[oldman]

Are you losing any fluid? Leaks? Did you bleed all calipers staring from the furthest one from the reservoir? Did you tighten down the bleeder valves enough? I suspect either you have leaks or you didn't bleed it properly.

 

[Defiant]

For what it's worth, I always bleed mine with the key in the "on" position.

To what effect? Bizarre.

I've heard people gravity bleeding as well with good results.

I've heard there's gold in them thar hills, too. But I ain't quitting my job and buying a shovel.
No, gravity bleeding won't do anything but waste a fair bit of time.

 

[hellotbone]

Well I started out with dirty fluid somwhat brown in color compared to the new clear stuff which is almost translucent. All calipers are flowing the new clear fluid.

I bought and changed for reman 2 front calipers because one had a siezed piston in it that I freed up but I felt could still be a problem. So last night I changed out the front calipers for these new ones and proceeded to bleed the brakes starting with the passenger side rear then driver side rear then passenger side front then driver side front. Farthest to closeest. Using both a vaccume bleeder and the standard way with a line and a bottle(I prefer the line and catch bottle). No air at all I bleed the brakes for 2 hours no foolin going in sequence from one to the other. Making sure the reservoir was always over 1/2 full so no air could have gotten in. After that the brakes were nice and firm with the car off after 1 pump. Start the engine and they fad almost 75% of the way to the floor every time. No matter what I do. I did all the manual tests to see if the master cylinder is leaking it isn't. I also did the tests as per the manual to test the booster and the check valve.

I drove it to work today and the firt time you hit the brake say if you hit it 2x slowing down it fades about 75% next time its near the top.

So my next question would be how far do you have to step on your brakes to feel feedback from the peddle?

 

[hellotbone]

Are you losing any fluid? Leaks? Did you bleed all calipers staring from the furthest one from the reservoir? Did you tighten down the bleeder valves enough? I suspect either you have leaks or you didn't bleed it properly.

Sir I have read another post on your brake bleeding technique and I used it in the shop as a print out guide so I did it per your instructions. No leakes at all looked everwhere with a good flourcent trouble light. All new brass washers on the banjoes etc...