Heater Vac Lines

[6SENSE]

Okay, heres a question that I didnt see a sticky for, nor found a answer to when searching. As many of us know those little cylindrical vac canisters over on the passenger side bolted to the heater box are usually broken. In fact on my car I never had one.
I know this: theres two nylon lines coming up from down the passenger side wheel well from the fire wall (from under the heater box). There is the hose that comes from the vac block (top of TB) by way of a check valve which also feeds the cruise control. There is also the vac line to the heater valve on the heater hose behind the turbo. I dont know if it makes any difference which one goes to which, but I have always had the vac block line connected to one of the pass side nylon lines and the heater valve to the other one. Now, getting to my question, I finally stopped BS'n and grabbed from the junkyard one of those cylindrical vac canisters [in perfect shape]. Now how do I plumb it in? Im guessing one of the lines from the pass side fender area goes to one connection on the canister, and the other connection goes to either the vac block line or the heater valve. Which ever it doesnt go to (vac block or heater valve) goes to the other nylon line at the pass fender. Any help is much appreciated.

 

[6SENSE]

Stopped and thought about it. It should go [inline] on the vac source line, right? Which would be the one originating from the vaccum block.
Anyway, thats what I went ahead and did and it seems to be working fine. Just wanted to verify.

 

[cool 84]

I would think that's how it goes. You need a vacuum source going to the cannister and the line going to your AC controls in the fenderwell going to another one. The reserve vacuum keeps the correct trap doors open/shut when you're under boost.

 

[6SENSE]

Thanks for the verification

 

[6SENSE]

Noticed today that I cant get anything to come out of the upper vents. Before installing the canister they would work, just not too good. Not much air would blow out compared to the lower floor vents, but now [since the canister install yesterday] nothing. Any ideas?

 

[cool 84]

I should remember how everything goes, I just mapped everything out a few months ago but my memory isn't that good. I got a vacuum canister from the junkyard and it wouldn't hold vacuum. It had a hairline crack that was very hard to see.

All I remember is one line going into the fenderwell is vacuum going to the AC controls and one is vacuum coming from the ac controls going to the heater valve by the turbo.

 

[6SENSE]

Thanks cool 84. I think I figured it out. I was checking for a leak out of the reservoir, after you mentioned the hairline crack on yours (thanks). Then I thought about it. Maybe it matters which port on the reservoir the vac source goes to (an in and an out), and Ive got it backwards. Switched em around and now the upper vents open. The larger port is where the vac source (from the vac block) goes to, and the smaller port goes to the dash.

Hopefully if anyone has this problem in the future this thread will come up in a search.

 

[redhotrod]

before you all close this thread, can you give me a little more insight on this. On my vacuum canister for the heater control, I only have 1 vacuum nipple. Its small, something like for a 1/8" vacuum line. This is the one that goes to direct vacuum? Where would the other line go and get to the heater controls? Is that a vacuum line that is coming through the firewall on the passanger side?
Isn't much info about this setup anywhere.

 

[6SENSE]

The type that I was refering to is the one that comes stock on 84/85 TRs. It also came on NA 3.8 Regals, which is where I found the piece. All of these that I had seen had two vac connections. The type that you have is probably similar to the round "ball" looking one that came on the 86/87s and just about every other vehicle. If it has only one vac connection, you wouldnt have the issue that the type I just installed has with a designated "in" and an "out".
I actually have a "1 vaccum nipple- vaccum ball" that I hooked up awhile back on the drivers wheel well, that I had sitting around from a '87. I "teed" it into the cruise control line which comes from the vac CV which also feeds the heater controls. I believe this is the way it goes on the 86/87s and the reason I did it like that, since I didnt have the 84/85 type till now (for a few years I had no vac reservoir at all). You could hook yours up the same way. Just tee into the vac source line (the line from the vac block by way of the CV).
Yes, the vac lines to the heater controls are over on the passeger side. They are nylon like the line for a boost gauge or mechanical oil pressure gauge. They come out of the firewall from up under the heater/AC box. If your heater setup is hooked up and just missing a vac reservoir, identify the line going over to the passenger side from the vac source and tee into it.

Hmm...now I have two vac reservoirs hooked up. Dont know if it helps anything at all, but it couldnt hurt I guess. At least I dont think so.

 

[redhotrod]

Thanks for the help! I believe mine is still the original '84 unit though.

 

[cool 84]

The extra canister is probably a good idea. I've been thinking about adding a second ball type too. I've heard when going up the grapevine to LA some people have had the cruise control stop working because the car is under boost or very low vacuum for so long the cruise uses up all the reserve.

 

[6SENSE]

Originally posted by cool 84
The extra canister is probably a good idea. I've been thinking about adding a second ball type too. I've heard when going up the grapevine to LA some people have had the cruise control stop working because the car is under boost or very low vacuum for so long the cruise uses up all the reserve.

That sounds good, except for the fact that my cruise control has never worked on this car I guess thats another topic though, huh? Havent really taken enough time to figure that one out yet.