It's the diaphragm

[orin@netcom.com (Orin Eman)]

Well I got a spare wastegate assembly from the junkyard for the huge
sum of $45 and did a dry run on disassembly...  It has the double
diaphragm and did hold vacuum in the upper chamber.  Diaphragm is in
poor condition though and isn't worth using.  So, I go out and disassemble
the wastegate on the car.  There was a small tear right at the back
where I can't see, but I could feel it.  It's somewhat bigger now...
My car has a single diaphragm though the double would fit.

So, I put it all back together and I'm back to overboost if I'm not careful.

Now, where to go from here?  What are these things made of?  It looks like
some kind of cloth and rubber.  It may be possible to patch a small tear.

Thanks for all the help,

Orin.