Replacing Vacuum Check Valve 1960 Electra

[Bill Stoneberg]

On my 1960 Electra I am thinking the vacuum check valve is bad because every time I accelerate or put my foot into it to go up a hill, my A/C warms up or doesn't blow as hard or blows through the wrong vents.

I have been through the compressor / hot gas valve etc and it cools well. I am thinking my actuators are losing vacuum and won't stay closed during low vacuum conditions or they are bad.

I thought I would try a vacuum check valve fist before spending lots of money to replace the actuators.

 

My problem is find the correct one and knowing how to test to see if it is bad.  Suggestions are welcome. I know I probably won't get a GM so replacement numbers are welcome. Doorman or something similar.

 

Mine has vacuum coming in and two outputs, one to the vacuum can and one to the actuators.

 

Bernie or Chris, have you ever replaced yours ?

 

Thanks

Edited August 13, 2017 by Bill Stoneberg (see edit history)

[avgwarhawk]

Bill,  I replaced the actuator by the firewall/outside.  Works the blend door I believe.  I can say it does stop working under heavy acceleration.    I agree your check valve is probably the cause.  If I remember correctly the repair manual is quite good showing each under dash actuator. etc.  Also,  the actuators are available.  In fact, I got mine at a business in TX if I'm not mistaken.   I can find out if you need me too.     As far as testing, a hand held vacuum pump should do the trick.    

[NTX5467]

To simplify things, I would investigate the inline vacuum check valves on the HELP! rack at the auto supply.  Many of these were used in the '70s to "delay" vacuum advance to the distributor on many different makes (usually Ford and GM).  Turn the delay valve backwards and it becomes a check valve.  Along about '85 or so, when Chevy 305 pickups ran their vacuum advance from manifold vacuum, after the trucks aged, they'd get "doggy" in how they ran.  The factory fix was a vacuum harness, two delay valves installed "backwards", in parallel, that replaced the normal single vacuum line going to the distributor vacuum advance.  This kept the vacuum advance charged long enough for the engine to build rpm and the centrifugal advance to come into play.  It worked great.  Not that you would need two in parallel, but one upstream of the existing check valve might be appropriate and could be hidden from view.  Might even find some at a salvage yard!

 

NTX5467

[Bill Stoneberg]

Chris,  I have found the actuators but I am trying the cheaper part first.  Found a doorman part that has promise.  My check valve had been replaced already one as it is a Ford replacement part :-)