Running A/C without vacuum

[nawlins-tim]

I've decided to keep my A/C and change what ever I need to get it running correctly. Several months ago While messing with it , I noticed a vacuum leak when the a/c is turned on. My motor doesn't make a whole lot of vacuum at idle , so any lost vacuum is real noticable.
So what I want to know is , has anyone out there ran there a/c WITHOUT the vacuum bulb attached? I kinda think it will work but what position will the air flow out of ? Or do yall think I'll have to alter the duct work? Any help is good help. Living in New Orleans it is crazy hot in a street rod . what I have is a 1980 El camino ss. thanks

 

[carmangary]

Sounds like you are thinking of going to a lot of trouble when all you need to do is fix the leaks. You ought to be able to isolate it by plugging tubes and tracking it down.

 

[Mike P]

I just got done setting up an aftermarket AC/Heat unit in my 83 El Camino so I got a chance to play with all that factory junk. Without vacuum it will default to the defroster mode. As mentioned fixing the problem may be the easiest route.

Your vacuum leak is either caused by a broken vacuum line (which can be a real PIA to track down) or a bad vacuum switch. To check for a line, run the controls thru the different modes and see what isn’t working. To check the switch simply pull the heater controls partially out of the dash and run thru the modes to see if that is where the problem is. The switches are still available by the way.

http://www.elcaminostore.com/el-camino- ... -1987.html

You MIGHT be able to access the door and figure out how to block it open by removing the dash vent and accessing it thru the center vent. Actually accessing the vacuum motor that runs the door is a PIA. You have to remove the dash, and then the driver’s side piece of ducting. Then you will find a small section of plastic marked “cut here for access”.

After you cut the hole the vacuum motor is inside. (You can see the hole I had to cut to remove the motor next to the big center vent.

There are a few more pictures of the ducting in my build thread if it helps:

viewtopic.php?f=13&t=12658&start=90

 

[RegalBegal]

Sounds like you are thinking of going to a lot of trouble when all you need to do is fix the leaks. You ought to be able to isolate it by plugging tubes and tracking it down.

After you find the leak, if your engine doesn't produce enough vacuum, you could install a vacuum pump.

 

[Bonnewagon]

The black vacuum ball is actually a reservoir to maintain vacuum under heavy load conditions when manifold vacuum normally drops. You may want to add a vacuum can like they use for power brakes as an additional reservoir. With the motor off and if there are no leaks and all is well, you should be able to move the AC controls and hear the vacuum doors opening and closing a couple of times before the vacuum runs out.

 

[joe_padavano]

The vacuum does two things for the A/C system. Most importantly, it is used to operate the various doors in the HVAC box under the dash. Second, it is used to close the heater valve (and shut off the flow of coolant to the heater core) but only when the A/C is on the MAX cold position. The compressor clutch and the heater blend door (that sets temperature) are not operated by vacuum at all.

If you disconnect vacuum to the system, the doors are spring loaded to send air to the defroster ducts and the floor vents. Nothing will come out the dash vents. As noted, the purpose of the vacuum ball is to serve as a reservoir for low-vacuum conditions. There is a check valve in the line between the vacuum ball and the manifold. This allows the vacuum ball to store vacuum under high vacuum conditions so that the HVAC operates properly during low vacuum conditions such as W.O.T. Obviously if there is a leak, this won't last long and the airflow will default to the defroster ducts and floor vents.

 

[nawlins-tim]

Thanks guys. Looks like for now if and when I try it out and I have a leak, I'll probably run it in the Default position. Defrost is very important and if it is cool enough I figure it won't take long to cool down the cab area of an Elky.
I did see the vacuum switch with the lines for sale at different sites. But actually I was always hesitant to remove ANY dash. I have done every kind of repair possible on any type of car but I never choose to mess with a dash. Especially an older model that already has squeeks and rattles of a 25yr+ vehical. And replaceing all those little hoses to track down one little leak Has Got to be a PITA and not the easiest route "carguygary". Thanks I'll let yall know what happens!!!!