Hollow Sound ('86 5kTQ)

[urq]

... the spring will probably fix the hollow sound, but chances are the
vacuum servo is disconnected, both mechanically and from the vacuum source,
so the recirc door will not move ... and the heater valve is on the same
vacuum circuit, so it may not be getting a signal either.  

Steve B
San Jose, CA (USA)

-----Original Message-----

The spring was missing, but was replaced. My mechanic luckily had 5 at his
garage. I also brushed off and vacuumed out the dirt and leaves in the AC
chamber. 

Max

-----Original Message-----

... ah yes, it's been so long I had forgotten!  This is a classic problem on
the T44 of your vintage.  I've even got the service bulletin in the folders
here somewhere.  What happens is the seal shifts and the recirc door sticks
shut.  When the HVAC tries to open it the vacuum motor mounting isn't strong
enough and the vacuum motor rips free from its moorings.  If your recirc
door is floating free it means that the spring is probably broken as well.
Do an archive search on recirc door for more info.  Funny, I did a spring on
one of the V8s not that long ago, I don't know why it didn't come to mind
earlier.  

Steve B
San José, CA (USA)

-----Original Message-----

I removed servo A illustrated on page 87.15, 87.22 & 87.23 in Bentleys from
under the thin plastic panel behind fire wall. When I moved the servo, the
servo made the same noise when I drive and hits bumps. Servo A controlling
the fresh/recirculation air flap right behind the evaporator coil broke off
from the arch support, which is not illustrated in Bentleys, looks weird in
Bentleys. Since the servo broke off the fresh/recirculation air flap is
always closed to prevent steamy windows when heating. Very difficult to
repair this servo connection. The servo is also called a vacuum motor in
Bentleys. There is a hose connected to the servo controlled leading to
solenoids under right dash from a vacuum chamber. 

When I drive I hope I just hope there in no more such noise