Ed Petry

Morning everyone,
Hope the day is going well for you.

MY 1981 5-speed. Manual heater/A/C control head. Functions appear to operate as they should (i.e., move the ****, expected result happens).

I am troubleshooting a vacuum leak in the cabin and need the advice of those more knowledgeable than myself.

First, thanks to everyone for the write-ups and pictures on this list. Helped a bunch.

Found one leak in the cabin by smoking the system. Fixed it.

I believe the hoses are correct on the control assembly, yet, I have a slight vacuum leak still.

Here is what I discovered:

"OFF" -- Vacuum leak heard in cabin (believe it is in the center of the cabin - maybe the control assembly)
"■■" -- Vacuum leak heard in cabin (believe it is in the center of the cabin - maybe the control assembly)
"▼" -- Vacuum leak heard in cabin (believe it is in the center of the cabin - maybe the control assembly)
"▼▲" -- Vacuum leak NOT heard
"▲" -- Vacuum leak NOT heard
"Defrost position" -- Vacuum leak NOT heard

Does this appear to be an internal issue to the control assembly or one of the vacuum units?

Thanks.

The Forgotten On

Most likely a vacuum diaphragm went bad. probably the footwell one, fortunately it is one of the easiest ones to get to.

Check all of them with a vacuum pump like a mity vac from the back of the control head and see.

Mrmerlin

please do a search for Wallys 928 HVAC system on 928GT.com

https://www.google.com/url?sa=t&rct=...LKZ3ayLDyrdKGQ

please read this,
then you will have a better understanding of how the system works and how to fix it

Ed Petry

Thanks for the help. Appreciate it.