Vacuum cannister differences

[Billabob]

My original vacuum ball got shattered into a thousand pieces and I’m noticing that there are quite a few variations on Ebay. Some are round and others are oval. Some have 1 inlet, others have 2 or 3. I bought the cleanest one thinking they are all the same but it only has one large inlet. I do not have a vacuum disconnect anymore but it would be nice to have the blend doors working. Does a single inlet ball equalize the pressure in the manifold enough that I can tee in the HVAC line elsewhere?

[87MJTIM]

The oval one is if you have cruise control.

[cruiser54]

HOrnbrod

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Posted November 21, 2016

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[Billabob]

1 hour ago, 87MJTIM said:

The oval one is if you have cruise control.

Not sure this is true since I have seen round ones with cruise control. My best guess is that the double nozzled ones are an inlet/hvac and the 3 nozzled one is inlet/hvac/cruise control. This one just has one inlet and no outlets. How does that work?

1 hour ago, cruiser54 said:

HOrnbrod

Apologies. I have a 1987 4WD Comanche. Cannister apparently is from a 1991 Comanche. 

[87MJTIM]

Sounds like yours may have been changed in the past.  Factory CC used the football reservoir.  You indicated that the cannister is from a 91.

[eaglescout526]

18 minutes ago, 87MJTIM said:

Sounds like yours may have been changed in the past.  Factory CC used the football reservoir.  You indicated that the cannister is from a 91.

Chrysler used the same shape football for their HOs. It can be confusing to those who aren’t familiar with parts(thanks Chrysler). 
 

OP, you will need the same shape canister but with 4 holes, two per side. They are getting harder to find these days. 

[cruiser54]

Billabob, do you have cruise? 

 

If not, here's a real easy way to upgrade and eliminate a bunch of troublesome plumbing. 

 

 

[cruiser54]

check this out. I cut a big one in half. 

 

It's basically 2 small cannisters in one. 

And, the "good" half of the can still works. 

 

[Ωhm]

@cruiser54    Do you remember if that was that the CC side or the HVAC side of that vacuum reservoir you cut off? I'm wondering if both sides have the check valve.

[eaglescout526]

31 minutes ago, Ωhm said:

@cruiser54    Do you remember if that was that the CC side or the HVAC side of that vacuum reservoir you cut off? I'm wondering if both sides have the check valve.

Wait….they’re different? I always figured they’re both the same. 

[Billabob]

This is all great info. I do not have cruise control. I also do not have a CAD disconnect anymore. I'm trying to simplify the hoses as much as I can. What I’m still confused about is how a stock 1991 is routed if the cannister has a single “nub”. Is there no check valve anymore? I always assumed the HVAC remained the same throughout all the 1996-down years. How did they get vacuum for HVAC without a nub for it? 

[Billabob]

As you can see, single inlet and no outlets. 

[Ωhm]

I would think that the single connect is both the inlet and outlet, no check valve. With the double connect, one inlet and one outlet, that should have an internal check valve.

[cruiser54]

Get this one and mount it under the coolant bottle. 

 

https://www.amazon.com/Dorman-HELP-47076-Vacuum-Tank/dp/B000COB8FA

[cruiser54]

6 hours ago, eaglescout526 said:

Wait….they’re different? I always figured they’re both the same. 

I don't remember