Hi all, once again I find myself needing to call on your collective wisdom. I've had a trawl about with the search function and got some tips, but still missing a few bits of info.
I did a track day at Silverstone on Sunday, the first in the A4 (1998 2.4 V6 saloon) and I found after about 3 laps I was getting epic brake fade and the pedal getting very soft and spongy. A 10 minute break and all was well again for another couple of laps, when the issue re-occurred.
Disks and pads are new up front (standard items) and the calipers seem to be free enough, so don't see too many issues there.
If I pump the brake pedal with engine off it gets hard as expected, but if I then turn on the engine it doesn't sink as I would expect. I can also hear a "hissing" sound at this point until I release the brake pedal. Not sure what to make of that.
The brakes are good enough (though not brilliant) on normal road driving.
So I guess my questions are: Is the servo goosed? Are the brakes usually "average" on an A4 or does it sound like somethings amiss? Am I expecting too much from the braking system? Are there any common/likely issues that I should be looking for?
Also, if I have to replace the servo, there is mention in Elsawin of needing a VAG tool to bleed the clutch after disturbing the brake master cylinder, is this the case or is there a DIY version? Vacuum bleeder perhaps?
Thanks in advance guys and gals.