Help fixing vacuum canister for vents

[dkmcgowan]

I need some help setting this up right.  I think I get it, but have a few questions.

 

I was having rough idle, then noticed my vents stopped working.  Did some searching on the forums and tracked the tubes down to the passenger fender and a vacuum canister.  It had tape on it with a crack, so was not fully holding vacuum, as well as the plastic line going down to it shattered in my hand from being weak.

 

So for now I decided to just plug the vacuum from the intake and leave the rest unhooked.

 

I plan to head to pull a part and find a new canister and mount it in the cabin like suggested here.

 

So my questions...

 

I had one extra line, taped to the primary vacuum source to the canister, that was not connected to anything, thinking maybe the original line?

 

I also had a T connector in the large primary vacuum line, was this supposed to T off to something that should be hooked up?

 

The grommet for the two small plastic lines going inside the firewall is separated from the firewall, can I push it back on somehow?

 

Also I keep hearing about check valves.  I do not have cruise, so the vacuum is only supporting the vents and the heat control system, how many check valves do I need and where should they be?

 

Can I find check valves at the pull a part, are they different for different years?

 

Lastly, my idle got better, I had a leak, but it's not perfect.  I ordered all new hoses, so I will replace everything, but do I need to unplug any sensors or the battery to reset this thing?

 

 

 

 

 

Here is the image showing the vacuum canister and the two lines that were hooked up to it...

 

 

 

 

This is me with the extra plastic line that was taped to the vacuum line that went nowhere on either end.

 

 

 

 

 

Here is my two connectors heading into the firewall.  Is this where a check valve should be?  This is the piece I'm curious if the grommet is supposed to be pushed into firewall material more or something?

 

 

 

 

 

Here is my other connector from firewall that connects to a new heater valve control

 

 

 

 

 

 

Here you can see the main vacuum source going to to the intake manifold.  It already had the T, I just disconnected a piece and capped it for now to fix the vacuum leak.

 

 

 

[HOrnbrod]

Factory vacuum supply setup, intake manifold to reservoir:

 

 

Junk the reservoir behind the bumper and move it into the engine bay. Here's how I did it:

 

http://comancheclub.com/topic/16154-vacuum-reservoir-relocation/?hl=vacuum

 

 

I use two check valves; one at the intake manifold vacuum source line, and one just before the reservoir.

 

[ParadiseMJ]

The vacuum system for the HVAC is really pretty simple.  As Hornbrod says, it's a piece of cake, and beneficial to relocate the reservoir.  If not just for ease of access, but also you'll eliminate a couple feet of vac line as well as taking it out of harms way from battery acid, mud and rough service.  The pink line coming out of the firewall just runs the heater valve, nothing else.  The black line comes from the reservoir, through the firewall and powers up all the HVAC controls.  There's a little "manifold" up behind the HVAC control system and operates the various servos that move blend doors and mode doors.

 

You'll find that there are many posts titled something like, "no air coming from vents", where the only air from the heater or A/C is coming out of the defrost vents, no matter what position the controls are set to.  When the HVAC loses vacuum it defaults to defrost. If the leak is small, it'll likely only default to defrost when you're accelerating or under load.

 

Two nipples on the vac reservoir, one large the "source".  The small one to the firewall and it may branch off to the cruise control servo, if equipped, and if you have 4wd and a vac disco axle.  That's how mine was set up before I eliminated the disco axle.

 

I would suggest that you buy new bulk vacuum line at NAPA or similar parts store, which is cheap, instead of patching any lines with tape etc.  NAPA also carries fittings like elbows, T's etc if yours are cracked or old/dried out etc.

[dkmcgowan]

What about the check valves? Mine did not have any, I've read some didn't and they are built into the canister and I've read they all should have them. If I need one which line would it go on and what kind do I need?

 

Also curious if the T could have been there from factory even though it was 2wd and no cruise control.

[HOrnbrod]

Every car on earth has inline vacuum check valves. They are available to fit any size tubing. The auto parts chain stores all carry them. As far as placement, already explained. 

 

[ParadiseMJ]

I only have 1 check valve, at the manifold, that I installed when I got the truck, as the HVAC vacuum system was gutted.  I had to rebuild it all from the diagram posted ^^^ up there.   I don't have cruise but I do have 4wd (without the vac disco axle now too).  So now I just have the one HVAC line from ball to firewall, everything else is new.

[dkmcgowan]

Perfect, thanks everyone, headed to pull a part to get a new canister tomorrow and a few other parts, then some fresh vacuum lines, and back together...

[dkmcgowan]

Did either of you replace new hoses all the way through the firewall, or did you cut the plastic on the engine bay side and push on fresh vacuum hose?