Minimarvel

Ok found the thread. I think the confusion yet again is the reference between how they should work (with the original parts) and how to make the system work with the new 2 port ones... Which don't work in function or form like the original unit. The new units (I am guessing... But very near to tearing one apart) have a single diaphragm that can be actuated fully by applying vacuum to either port..... Which completely defeats the point of application and further creates the problem as without a check valve in some configuration of controls you have either fully open or fully open or nothing as in some positions this would create a massive vacuum leak. As has been said. The old ones are a 2 diaphragm 2 stage device... The new ones are a 2 port single diaphragm single action device.... That's the confirmation I really need as if so they can never work without modification to the circuit or system.

If you read page 3 of this blog it explains the issue fully and mentions the "fix".

Thanks guys for all your inputs.... But I am still none the wiser.... And this is the problem. I am an engineer so get completely how the system should work. Even gone one stage further by measuring the vacuum and setting it all up on a bench so to speak. My thoughts are that the new diaphragms are not the same as the original units because they only have a single diaphragm. Reading more... This apparently has been confirmed by the manufacturer at some point. What I really need is to hear from someone who has actually done it using the new actuator. The original is different also because there is a check valve internally. Single port actuators are available from many sources such as ebay and Alibaba... They are predominately used for waste gate usage on newer cars. If a single diaphragm with 2 ports is used without a check valve internally... The second port becomes the "leak" if you follow me under some settings. The selector switch on the 65 is not a tightly sealed unit thus it requires accumulative vacuum to work correctly, otherwise there will never be enough power to overcome the spring in the different doors of the system. But I am more than happy to be educated by someone who has actually done it.

No I definately have a 65...and know they are completely different, but the 2 port actuator is a 2 port actuator.... And not apparently a 2 stage actuator... But the rules must be the same. As said, I modified the Stv to an electronic switch.... Low coolant protection installed to protect the pump and a thermostat to control the temp in the car.... Just like a new Ford.... but all look stock, which is enough for me. Just don't quite understand why these pesky actuators don't work. There is not even any info on them anywhere... As said... If the fix is to feed both ports from one line, why bother having a 2 port valve.... Something doesn't make any sense. Greeting from a lovely spring England... Regards David

And I have searched again.... Any idea what section it's in... Or heading.....? Much thanking...

Thank you sir, Yes I am a member and indeed searched for this earlier... Maybe you might post a link. Not worried about the stv side of things as vac line blocked and stv modified to electronic with pressure switches in circuit etc. Only these damn actuators. The advice is to buy the expensive 2 port ones and then today I read that you feed both ports with one line.... Which makes me ask... Why not just use a simple $10 single port actuator in the first place? If we cannot buy a 2 "stage" actuator then what use is a 2 port one... You can see the confusion. Kindest Regards David

Sorry to re-open this topic, but a little clear advice needed... I have a 65 Riv. Both Vacuum actuators on the A/C system where shot and had someone try to repair and re-seal them previously, thus I bought 2 of the 2 port units from "old air". All vacuum lines replaced and the whole system overhauled yet the doors still don't work well.. If at all. I found this thread which in part explains all but I am desperate for some clarification. The original vacuum actuators were 2 stage having 2 diaphapms inside and some form of check valve. The new ones are simply 2 port with a single diaphragm inside thus could you give me guidance on the correct "wiring" of the new ones. I understand they will now be either open or shut and not half open etc, so do I... Remove the vac tube that went to the outer connector of the original actuator and plug it.. Then take the vac tube that went to the center port of the original actuator, connect a "y" piece and connect both ends of this "y" to both ports of the new actuator. Many thanks guys... Fed up with the block of wood falling out... If you follow me..