Vaccuum lines for the HVAC...WTF??

[turbonut85]

OK. This is a dumb question, but, What is the correct hose routing for the HVAC?? I have converted my 85 GN from the electronic climate controls to a spare 87 manual set up I had laying around...Changed the WHOLE heater box!! The two vaccuum lines from the heater box are naturally different lengths than the original set up. (The car was wrecked on the pass side so I have never seen it all together) So, the question is, does the 87 set up use the twinkie shaped vac cannister that was mounted to the top of the heater box? If so do I connect one line to it from the heater box and one to a vac supply? and where does the heater valve connect? What am I missing??? Any help would be appreciated.:redface:

 

[turbonut85]

anyone???

 

[BRAD_PADGETT]

I have the original stock 85 vacuum diagram. My scanner is broken so I will have to post a pic. Be patient. Brad

 

[BRAD_PADGETT]

Let me know if you can read this. Thanks-Brad

 

[summit]

87 models did not use the 'twinkie".

 

[youngstr]

How about an 87 diagram?

I have an 85, person I bought it from was upgrading the electronics to 87, does anyone have an 87 vacuum diagram? I'd like to cross reference so I can see where he was at in the conversion, so I can finish it. if someone could post one that would help me a lot. thanx

 

[turbonut85]

Thanks guys. Brad, I have the same diagram on my fan shroud. It doesn't show the two hard plastic lines that come from the inside of the car with the heater box wiring, and what they connect to in the engine compartment. Or, how the heater valve is incorporated in the whole system. Summit, Did the 87use a different cannister to store the vaccuum pressure? Is the difference between the 85 and the 87 in the vaccuum block or in the rest of the vaccuum system. Is that why the 87's didn't use the twinkie cannister? ---Keith

 

[turbonut85]

I have an 85, person I bought it from was upgrading the electronics to 87, does anyone have an 87 vacuum diagram? I'd like to cross reference so I can see where he was at in the conversion, so I can finish it. if someone could post one that would help me a lot. thanx

I have the 87 vac diagram on the top of my heater housing. I'll take a pic for you and try to post it friday. ---Keith

 

[youngstr]

just what I need

Good deal, thanx, I'll grab it Sunday, going down to englishtown tomorrow till then.......need a weekend off.

 

[6 to go]

The 87 vacuum canister is a round one that mounts on the
driver inner fender under the air cleaner box.
The 84/ 85 canister draws vacuum from a fitting on the
back of the intake manifold. HTH some.

 

[BRAD_PADGETT]

Thanks guys. Brad, I have the same diagram on my fan shroud. It doesn't show the two hard plastic lines that come from the inside of the car with the heater box wiring, and what they connect to in the engine compartment. Or, how the heater valve is incorporated in the whole system. Summit, Did the 87use a different cannister to store the vaccuum pressure? Is the difference between the 85 and the 87 in the vaccuum block or in the rest of the vaccuum system. Is that why the 87's didn't use the twinkie cannister? ---Keith

I have the shop manuals and will look it up this afternoon. I will also check my car and post later today. Brad

 

[BRAD_PADGETT]

I have an 85, person I bought it from was upgrading the electronics to 87, does anyone have an 87 vacuum diagram? I'd like to cross reference so I can see where he was at in the conversion, so I can finish it. if someone could post one that would help me a lot. thanx

I have converted my car to the 86/87 ECM, IGN, MAF and electric fan. There were no vacuum line changes. Good luck. Brad

 

[Boost231]

you dont need any vacum lines. only ones i have on my car is 1 to the fuel pressure regulator and one to the map sensor.

 

[turbonut85]

Let me know if you can read this. Thanks-Brad

That sure looks like a new or repro sticker. Where might I get a sticker like that one??

 

[turbofish38]

Okay on the 2 lines going in and out of the firewall. One supplies vacuum to the water control valve and the other is the vacuum source. On a hot air motor the vacuum source was at the throttle body. The vacuum block on top. On the LC2 motor there was a metal tube running down the right side of the motor from the vacuum block. On both motors the set up was a hose coming from the source than a check valve. From the check valve one hose went to the HVAC and the other went to the cruise control/vacuum reservior. You can use either the Twinkie or the softball. A vacuum tank is a vacuum tank. Use the pic Brad posted to see how there is a tee in the line that supplies the vacuum to the cruise and vacuum tank. The set up is the same for any G-Body. One hose for the source. One hose for the water control valve.

 

[turbonut85]

Do I need the check valve inline from the vac source to the HVAC or inline with the cruise?

 

[turbonut85]

I have an 85, person I bought it from was upgrading the electronics to 87, does anyone have an 87 vacuum diagram?* I'd like to cross reference so I can see where he was at in the conversion, so I can finish it. if someone could post one that would help me a lot. thanx

Here are the 87 diagram pics, HTH Sorry they are so fuzzy:redface: