Re: '85 4000sQ at Audi dealer

[rwcohn@chinet.chinet.com (Robert W. Cohn)]

> 
> Well, after some thought, I bought the car...  It was just too good to pass
> up...
> 
> --Eric
> 
> 

Well Eric,  First check the ground stud on the intake manifold.  Both the 
ignition and the differential pressure regulator use this ground point as
ground.  The second thing to check is the formed rubber hose that runs
between the intake manifold and the air bypass motor.  Simply replacing the
hose will work only temporally, as the hose will crack again soon.  To 
prevent it from continually cracking and causing a vacuum leak you'll need
to make a simple modification to it (actually an addition).  I used a piece
of the black vacuum tubing that VW uses to run between the intake manifold
and the brake booster.  This hard tubing is well suited for the purpose, as
it is meant to take the underhood heat.  In that the rubber hose has three 
outlets the tubing that you insert into the hose to prevent it from 
collapsing on itself, will need to have a slight bend and a hole where the 
smaller hose outlet is.  The first time I found the cracked hose I replaced
it.  Then in less than three months it cracked again.  In that the hose was
basicly new, (still had the waxy rubber protectly stuff on it) I simply
cleaned the hose with brake clean, including inside the crack.  To seal the
crack I used the Grey RTV (I think it's #499) it's the firmest standardly
available RTV that you can get (great stuff).  You'll need to pinch the 
tube so the crack is opened up a bit, then smear the RTV into the crack.
Remember that it will be subjected to vacuum, so an additional build up 
on the outside will prevent it from being injested by the hungry motor.
Of course you can buy a new hose, add the tubing and not worry about it 
again.   ENJOY!  

Robert.....
rwcohn@chinet.com