A/C and Cruise Control Vacuum Source

[paulrowe]

Where are you guys pulling you vacuum sources for the Air conditioning and Cruise Control? Do I use the carb ports or the back intake port. I think the back intake port is for the transmission modulator??? Should I tee into that or go somewhere else? Any advise would be appreciated. I'm not sure where it was all hooked up as most was disconnected by the PO.
I downloaded all the vacuum diagrams but not sure if I need port or straight manifold vacuum as it doesn't show a source. Are the small nipples on the carb for port and the big for straight vacuum?

 

[75gmck25]

I have a vacuum fitting screwed into the back of my intake. From that line I have a T to get vacuum for the A/C and the TH350 modulator. My distributor vacuum advance is connected to a small port on the Quadrajet and the brake booster is on the large fitting on the back. PCV valve is connected to large port on the front of the carburetor. I believe this is the stock setup.

Bruce

 

[PrairieDrifter]

The ac vacuum tube is very small plastic tubing that runs from inside to the heater controls, then out and across the firewall, then turns into very small rubber tubing(easily available), then to a check valve, the check valve connects to a vacuum canister, and also goes to an intake port behind the carb for manifold vacuum. I also will include a picture of the plastic tube that runs through the firewall and the factory style routing, added note I would replace most of that plastic tubing, at least on the engine bay side, you do need some of it inside I believe. Everything is basically factory other than my modifications and aftermarket parts. The rubber line next to the green steel line, goes from the intake port to the check valve, then the green steel line is the brake booster line, both manifold vacuum.

Then the brake booster manifold vacuum goes to a port on the back of the carb, a quadrajet anyways, as far as I know the steel line is factory, just slightly tweaked.

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[PrairieDrifter]

I can't help on the cruise control, I can't remember that long ago as I didn't care for it and ripped it out right away. That's also why my system is a simplified orignal ac truck with an ac delete, delete box and everything. Also I want to specify my truck is an 84 as there may be slight differences, but they should be similar.

 

[Craig 85]

These are for later model truck, but hopefully it may help. Look at the lower left in the first diagram for the basic hose connections. The second is how it looks on my '85, but I believe it is different style cruise control pod than yours.

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[Grit dog]

I’m no expert but the AC Controls I say need to run off of manifold vacuum so that it functions at idle.
Cruise can run off of either, as you never use cruise function without throttle partially open.

 

[AuroraGirl]

I’m no expert but the AC Controls I say need to run off of manifold vacuum so that it functions at idle.
Cruise can run off of either, as you never use cruise function without throttle partially open.

Real men idle down the freeway

 

[paulrowe]

Hey thanks guys for the information. I bought some tees to hook up the trans modulator and the vacuum canister for the A/C. And I'll hook up the cruise control to a port on the carb somewhere. Thanks for the diagram Craig85!

 

[paulrowe]

I hope all this stuff Will work. I had plans to buy the vintage air kit but it is way to much to spend right now especially when converted to Canadian dollars. I spent a few hundred restoring the old system instead.

 

[Big Chip]

I hope all this stuff Will work. I had plans to buy the vintage air kit but it is way to much to spend right now especially when converted to Canadian dollars. I spent a few hundred restoring the old system instead.

My understanding is that the compressor is the biggest problem on the old stock systems. There's a Sanden compressor that you can get that is a lot better but someone else will have to chime in on that. Personally I prefer the stock controls to the look of the Vintage Air one's so I too am going to rebuild my current system someday.

 

[Joshua Keith]

I have my cruise control running off of manifold vacuum. It tees into my a/c vacuum line. Never gives me an issue. I have read that the transmission vac switch needs to run off of ported vacuum, but other opinions may vary. sorry for the poor drawing, but this is how I have mine ran. The orange lines are where I have check valves.

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[Craig 85]

My understanding is that the compressor is the biggest problem on the old stock systems. There's a Sanden compressor that you can get that is a lot better but someone else will have to chime in on that. Personally I prefer the stock controls to the look of the Vintage Air one's so I too am going to rebuild my current system someday.

That's what I did on mine. It's all OEM except the compressor and brackets. In the end, with buying all the OEM type parts to rebuild the complete system, I'm probably close in cost to the Vintage Air unit. I've had a couple of the aftermarket A/C systems before. One thing I never liked about those was the fan blower is in the cab which creates more interior noise, thus the reason for me sticking with the stock system. And I agree about the looks of aftermarket.

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[Grit dog]

Real men idle down the freeway

Strange reply....but nontheless expected I suppose, considering the source.

 

[AuroraGirl]

Strange reply....but nontheless expected I suppose, considering the source.

Its meant to be a joke.. but okay. Obviously not a serious statement.

 

[Al92toyo]

I just had my 454 rebuilt and I am going with a RestoMod A/C system (similar to Vintage Air). I am also converting it to Fuel Injection through a Holley Sniper kit. What all vacuum lines to I need to keep and where should I plug them in to? Brake Booster, Transmission, Cruise Control, anything else I'm not thinking of?