heater ac vacum controls

[ozbowhunter]

so while im working on the interior and waiting on some parts can anyone tell me what to look for in regards to a slow/sluggish vacuum control on the ac heating control when switching vents etc

[gmachinz]

The achille's heal is the plastic blend door rod attachment-it's held in place by a 7mm machine screw and over time it breaks off the plastic every time-when this happens, you've effectively lost control of the vacuum controls ability to fully open the blend door-if this happens, it defaults to mainly just blowing on the floor and won't be able to do anything through the vents. I recently restored my entire enclosure while I was replacing the heater core. I found a blend door that had one still intatc but it was cracked-so I plastic weld expoxied it in place like crazy now she'll never break! Blend door will always open and close now.

[ozbowhunter]

ok where do I find this blend door? so I can see what I need to door thanks

[Low87]

You can get the plastic attachment through either LMC or Classic, can't remember which. It's cheap, less than $10. Someone needs to make a metal replacement.

[ozbowhunter]

is it number 18 on this page???
http://www.lmctruck.com/icatalog/cc/full.aspx?Page=58

[gmachinz]

#18 is the vacuum wheel which is inside the climate control panel-it has a spring that keeps pressure against a seal and redirects vacuum as you slide your lever across. The piece that attaches to the main blend door isn't available as far as I know....could be wrong tho....I'll hafta check on that one.....yeah...a metal one would be nice.....GM had a stupid attack when they approved that design that's for sure.
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[ozbowhunter]

so where is this blend door to be honest I don't even know what im looking for or where to get into to sort this out what part do I need to open to find this blend door ?

[gmachinz]

Well, that's the fun part...hee hee....you'll have to pull the entire underdash climate control enclosure out from under the dash and inspect the door-its between the enclosure and firewall so there's no way to even see it unless you pull it down.
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[ozbowhunter]

Dammmm that's not what I wanted to hear ..... Oh well it's got to be done will let you know how it goes
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[harvey85]

Hope this guy doesn't mind, found a lot of informative stuff on this thread.
http://67-72chevytrucks.com/vboard/s...d.php?t=463885