65 Heater Control Vacuum Leak

[fatbuick]

Hi all,

I couldn't get any vacuum to the heater tap (red vac line) and I notice that when I slide the control lever to the right with engine running there is a leaking vac sound from the area shown

(is that the modulator?)

Also the unusual washer shown is loose and doesn't seem to be doing anything. What is it supposed to do?

I put a vac line directly from the Vac Tank to the heater tap and that works. Plenty of heat once the water started flowing.

Any ideas to get it working how it should would be great thanks and where I can buy parts if they're available please.

Regards

[Jim Cannon]

Yes, that is your modulator. It supplies vacuum of varying levels to the A/C Suction Throttle Valve. They frequently fail and I know of no source. It does not directly control vacuum to the heater valve. I suppose if it introduced a really bad vacuum leak, not enough vacuum would get to the other parts of the system. I suspect the selector valve is not working properly, but I am less familiar with the '65 system than I am with the '63.