Fixing Leaky TB, was IC inlet O-ring size?

[Jesse Clendenning]

I just did the same pressurization test on my throttle body a couple months
ago. I too found that my throttle body leaked in the same place as yours. I
then tried 2 other throttle bodys with the same results. All were MC
variety. I tried soaking the seals in hydralic jack oil, tranny fluid, to
make them swell but they still leaked.

I determined that all throttle bodies (at least older ones) leak and since
no one else had noticed (couldn't find anything in the archives), the leak
could not be causing a substancial loss in boost pressure or an appreciable
vacuum leak.

These are my observations.


----- Original Message -----
From: "Jim Green" <jeg1976 at yahoo.com>
To: "Quattro list" <quattro at audifans.com>
Sent: Friday, July 26, 2002 12:12 AM
Subject: Fixing Leaky TB, was IC inlet O-ring size?


> >
> > My homemade plug just pressurizes the entire intake
> > system...it also
> > ends up pressurizing the crankcase too, which is why
> > you should watch
> > for the dipstick shooting out(this happened to me
> > once, when I had
> > too small an o-ring on it.)
> >
> > Pressurizing the entire system is by far the
> > quickest, safest, and
> > easiest way to find boost leaks.  Uh, yeah, I think
> > I'll wander
> > around the engine compartment with a unlit propane
> > torch.  Uh, NOT.
> >
> > Especially when used with one of those portable air
> > tanks, you can
> > -instantly- tell, simply by listening, where leaks
> > are and how bad
> > they are.
> >
> >
> > >Also, why did you say only 10 psi or so when
> > pressurizing.  Is that
> > >because you don't want to exceed the 1.8 bar that
> > is typically
> > >pressurized on the stock set up?
> >
> > Yes- the ECU pressure sensor could be damaged
> > otherwise.  I would
> > have said 14psi, except that leaves no margin for
> > error; 2bar is the
> > max rated pressure for that sensor.
> >
> >
> > Brett
>
> On that note, my throttle body is leaking pretty bad
> at the pivots, giving a nice hissing sound under
> boost.  It's of the KH variety.  Anyone had any luck
> fixing something like his?
>
> Thanks,
>
> =====
> Jim Green
> '89 90tq 034EFI, Haltech IG5
> http://www.geocities.com/jeg1976/car_home.html
>
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