Vacuum reservoir?

[Norwester]

See below

 

[Norwester]

Ok,Ok....I'll keep messing with it. What diameter are the hoses I'm looking for? I'm not sure if some of the things I see are electrical or hoses.
Also, I see a vacuum diaphram on the passenger side kickplate with no hose on it. What does it control?

I really see the remnants of somebody being under this dash. Lots of loose wires and things disconnected. What a rat's nest.

here are pics through the ashtray and through the glove box

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[chengny]

Dont give up yet. It really is rather simple. Do yourself a favor and remove the ash tray. Its only four screws. That will help you see in there.

Yeah, George is right. And also understand that the images above were taken during a A/C modification. At that point, the duct work (that is preventing you from seeing the firewall penetration) was not installed yet. I only provided them for the sake of clarity


I'm sure what you are seeing looks more like this:

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An easy way to access and inspect a big part of the A/C vacuum harness is by pulling the glove box. There is a plastic hinge at the bottom of the GB that is screwed to the lower dash panel in 4 places. Just release the screws and remove the entire glove box:

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With both the glove box and ashtray removed, you should have a good view and even some room to get your hands in there.
Plus I noticed that some ducting was missing and other pieces had screws missing.

Hate to do it but I may have to take it to a Chevy dealer.

Unfortunately, if you have pieces of the ducting missing - depending on which ones - the dealer probably won't have them. Most of this stuff is NLA. Hit the junkyards.

The worst thing however, is that there is no sign of a vacuum supply hose (or electrical harness) coming through the firewall and into the engine compartment. That generally means that at some point, someone decided they didn't want A/C anymore and...just went Neanderthal on the system. Note the way that the wiring harness to the engine controls was disconnected when the ECM was "decommissioned":

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Not exactly what you'd call "surgically removed".

I have a bad feeling that the A/C harness (that once ran into the engine compartment) suffered a similar fate - and that you will only find 5 diked off leads and one snipped gray vacuum tube on the cab side.

Frankly, I wonder how your blower is even running. There must be a patched in (and rerouted) set of leads that feed from the control head to the resistor, relay and blower motor. They usually come through that empty hole in the fire wall.

 

[Norwester]

Jerry,

In your #2 pic, you're showing some lines joining at a tee. See below for a pic of mine. One end is disconnected. Kind of a funny rubber connector on the end.

Do I have to remove ducting to route the lines?

Just how many different hoses are in there?

I'm going to remove my gauge face plate in order to replace the shift indicator....will I see the back of the ac/vent/heat controls and will it do me any good?

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[chengny]

Before you spend any more time trying to "reboot" this system - read what I just posted.

Investigate and determine what happened to the wiring harness and vacuum supply hose that used to transit the firewall through the rubber grommet.

It is possible that those 5 wires and vacuum hose were just carefully withdrawn into the cab and are neatly coiled up with a wire tie on top of the air handler - but somehow I doubt it.

I don't know how gung-ho you are about getting this A/C system back up and running; but if those wires are cut and the engine compartment harness is gone...you have some splicing to do.

But don't bum out. Like I said , the entire HVAC wiring harness into the engine compartment consists of only 5 leads. And extending the vacuum supply hose back out to the manifold would be easy.

Don't worry about the vacuum hose routing and components inside the cab right now. Getting that straight is way down the road.

But if you are determined to hook up the interior vacuum system, that hose coming off the tee should connect to the actuator located behind the half-cup shaped protector on the RH kick plate:

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[Norwester]

Again...appreciate your help. You've been patient. I think I mentioned that my auto skills are low to medium.

Not interested in a/c, just heat, vents, and defrost. Half the ac components under the hood are either missing or broken.

That is an odd connector on that loose hose. How does it connect to the actuator on the RH kickplate......and what does it do?

Done for the day. Too hot. Too hungry!

Thanks!

 

[Georgeb]

TrY looking at this thread.

http://www.gmsquarebody.com/forum/showthread.php?t=2875&page=2

 

[Georgeb]

I also have a complete cab harness froma n AC truck as well as the heater box and vacuum lines if you need parts

http://www.gmsquarebody.com/forum/showthread.php?t=13334

 

[Norwester]

That's a helpful link, George...thanks!

 

[Norwester]

OK...tired of looking under the dash. Ole body starts barking.

Its time to work out a vacuum source from the engine.

Is it best to tap into the Edelbrock manifold or would it be better to tap into another existing source of vacuum? If I were to use an existing line, would I still insert a check valve before the tee?

The vacuum line attached to the reservoir is 5/32. Do I want to use this size throughout?

Thanks!

 

[chengny]

If I were to use an existing line, would I still insert a check valve before the tee?

Yeah, you really should. Otherwise when your manifold vacuum goes away, so to will your reserve vacuum in the tank (air from the manifold will just blast up the tube) and the control system will be inop.


As far as tubing size - IDK, whatever you have around that fits is okay. I think I use windshield washer tubing. It is durable and cheap.

 

[Norwester]

If I were to use an existing line, would I still insert a check valve before the tee?

Yeah, you really should. Otherwise when your manifold vacuum goes away, so to will your reserve vacuum in the tank (air from the manifold will just blast up the tube) and the control system will be inop.


As far as tubing size - IDK, whatever you have around that fits is okay. I think I use windshield washer tubing. It is durable and cheap.

Thanks, Jerry. I started looking around for the fittings to go from the manifold itself. Having a bit of trouble finding everything that matches up sizewise. I did buy some 5/32 hose and a 3/16 check valve. Having trouble finding a manifold fitting that will transition to the 5/32 hose, even with reducing connectors.

Would I be better off tapping into an existing vacuum hose or should I still try to put something together from the manifold?

It sounds like the size of the line isn't important. Looking at the hoses under the dash, I can see why.

 

[Georgeb]

I would tee in right here and have my check valve close to the tee to increase the stored vaccuum.

 

[Norwester]

I would tee in right here and have my check valve close to the tee to increase the stored vaccuum.

I just found the fittings I need to tap into the manifold. Is there a downside to doing it this way?

Thanks for your help

 

[Georgeb]

I just found the fittings I need to tap into the manifold. Is there a downside to doing it this way?

Thanks for your help

Nope, go with it.